              Frequently Asked Questions for FreeBSD 8.X, and 9.X

  The FreeBSD Documentation Project

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   Abstract

   This is the FAQ for FreeBSD versions 8.X and 9.X. Every effort has been
   made to make this FAQ as informative as possible; if you have any
   suggestions as to how it may be improved, please feel free to mail them to
   the FreeBSD documentation project mailing list.

   The latest version of this document is always available from the FreeBSD
   website. It may also be downloaded as one large HTML file with HTTP or as
   a variety of other formats from the FreeBSD FTP server.

   [ Split HTML / Single HTML ]

     ----------------------------------------------------------------------

   Table of Contents

   1. Introduction

   2. Documentation and Support

   3. Installation

   4. Hardware Compatibility

                4.1. General

                4.2. Architectures and Processors

                4.3. Hard Drives, Tape Drives, and CD and DVD Drives

                4.4. Keyboards and Mice

                4.5. Other Hardware

   5. Troubleshooting

   6. User Applications

   7. Kernel Configuration

   8. Disks, File Systems, and Boot Loaders

                8.1. ZFS

   9. System Administration

   10. The X Window System and Virtual Consoles

   11. Networking

   12. Security

   13. PPP

   14. Serial Communications

   15. Miscellaneous Questions

   16. The FreeBSD Funnies

   17. Advanced Topics

   18. Acknowledgments

   Bibliography

   List of Tables

   3.1. Maximum File Sizes

   List of Examples

   10.1. "InputDevice" Section for Wheeled Mouse in Xorg Configuration File

   10.2. ".emacs" Example for Naive Page Scrolling with Wheeled Mouse
   (optional)

                            Chapter 1. Introduction

   1.1. What is FreeBSD?

   1.2. What is the goal of the FreeBSD Project?

   1.3. Does the FreeBSD license have any restrictions?

   1.4. Can FreeBSD replace my current operating system?

   1.5. Why is it called FreeBSD?

   1.6. What are the differences between FreeBSD and NetBSD, OpenBSD, and
   other open source BSD operating systems?

   1.7. What is the latest version of FreeBSD?

   1.8. What is FreeBSD-CURRENT?

   1.9. What is the FreeBSD-STABLE concept?

   1.10. When are FreeBSD releases made?

   1.11. Who is responsible for FreeBSD?

   1.12. Where can I get FreeBSD?

   1.13. How do I access the Problem Report database?

   1.1.  What is FreeBSD?                                                     
         FreeBSD is a modern operating system for desktops, laptops, servers, 
         and embedded systems with support for a large number of platforms.   
                                                                              
         It is based on U.C. Berkeley's "4.4BSD-Lite" release, with some      
         "4.4BSD-Lite2" enhancements. It is also based indirectly on William  
         Jolitz's port of U.C. Berkeley's "Net/2" to the i386(TM), known as   
         "386BSD", though very little of the 386BSD code remains.             
                                                                              
         FreeBSD is used by companies, Internet Service Providers,            
         researchers, computer professionals, students and home users all     
         over the world in their work, education and recreation.              
                                                                              
         For more detailed information on FreeBSD, please see the FreeBSD     
         Handbook.                                                            
   1.2.  What is the goal of the FreeBSD Project?                             
         The goal of the FreeBSD Project is to provide a stable and fast      
         general purpose operating system that may be used for any purpose    
         without strings attached.                                            
   1.3.  Does the FreeBSD license have any restrictions?                      
         Yes. Those restrictions do not control how you use the code, merely  
         how you treat the FreeBSD Project itself. If you have serious        
         license concerns, read the actual license. For the simply curious,   
         the license can be summarized like this.                             
                                                                              
           * Do not claim that you wrote this.                                
                                                                              
           * Do not sue us if it breaks.                                      
                                                                              
           * Do not remove or modify the license.                             
                                                                              
         Many of us have a significant investment in the project and would    
         certainly not mind a little financial compensation now and then, but 
         we definitely do not insist on it. We believe that our first and     
         foremost "mission" is to provide code to any and all comers, and for 
         whatever purpose, so that the code gets the widest possible use and  
         provides the widest possible benefit. This, we believe, is one of    
         the most fundamental goals of Free Software and one that we          
         enthusiastically support.                                            
                                                                              
         Code in our source tree which falls under the GNU General Public     
         License (GPL) or GNU Library General Public License (LGPL) comes     
         with slightly more strings attached, though at least on the side of  
         enforced access rather than the usual opposite. Due to the           
         additional complexities that can evolve in the commercial use of GPL 
         software, we do, however, endeavor to replace such software with     
         submissions under the more relaxed FreeBSD license whenever          
         possible.                                                            
   1.4.  Can FreeBSD replace my current operating system?                     
         For most people, yes. But this question is not quite that            
         cut-and-dried.                                                       
                                                                              
         Most people do not actually use an operating system. They use        
         applications. The applications are what really use the operating     
         system. FreeBSD is designed to provide a robust and full-featured    
         environment for applications. It supports a wide variety of web      
         browsers, office suites, email readers, graphics programs,           
         programming environments, network servers, and just about everything 
         else you might want. Most of these applications can be managed       
         through the Ports Collection.                                        
                                                                              
         If you need to use an application that is only available on one      
         operating system, you simply cannot replace that operating system.   
         Chances are there is a very similar application on FreeBSD, however. 
         If you want a solid office or Internet server, a reliable            
         workstation, or just the ability to do your job without              
         interruptions, FreeBSD will almost certainly do everything you need. 
         Many computer users across the world, including both novices and     
         experienced UNIX(R) administrators, use FreeBSD as their only        
         desktop operating system.                                            
                                                                              
         If you are migrating to FreeBSD from some other UNIX(R) environment, 
         you already know most of what you need to. If your background is in  
         graphic-driven operating systems such as Windows(R) and Mac OS(R),   
         you may be interested in using PC-BSD, a FreeBSD based distribution, 
         instead. If you have not used UNIX(R) before expect to invest        
         additional time learning the UNIX(R) way of doing things. This FAQ   
         and the FreeBSD Handbook are excellent places to start.              
   1.5.  Why is it called FreeBSD?                                            
           * It may be used free of charge, even by commercial users.         
                                                                              
           * Full source for the operating system is freely available, and    
             the minimum possible restrictions have been placed upon its use, 
             distribution and incorporation into other work (commercial or    
             non-commercial).                                                 
                                                                              
           * Anyone who has an improvement or bug fix is free to submit their 
             code and have it added to the source tree (subject to one or two 
             obvious provisions).                                             
                                                                              
         It is worth pointing out that the word "free" is being used in two   
         ways here, one meaning "at no cost", the other meaning "you can do   
         whatever you like". Apart from one or two things you cannot do with  
         the FreeBSD code, for example pretending you wrote it, you can       
         really do whatever you like with it.                                 
   1.6.  What are the differences between FreeBSD and NetBSD, OpenBSD, and    
         other open source BSD operating systems?                             
         James Howard wrote a good explanation of the history and differences 
         between the various projects, called The BSD Family Tree which goes  
         a fair way to answering this question. Some of the information is    
         out of date, but the history portion in particular remains accurate. 
                                                                              
         Most of the BSDs share patches and code, even today. All of the BSDs 
         have common ancestry.                                                
                                                                              
         The design goals of FreeBSD are described in Q: 1.2, above. The      
         design goals of the other most popular BSDs may be summarized as     
         follows:                                                             
                                                                              
           * OpenBSD aims for operating system security above all else. The   
             OpenBSD team wrote ssh(1) and pf(4), which have both been ported 
             to FreeBSD.                                                      
                                                                              
           * NetBSD aims to be easily ported to other hardware platforms.     
                                                                              
           * DragonFly BSD is a fork of FreeBSD 4.8 that has since developed  
             many interesting features of its own, including the HAMMER file  
             system and support for user-mode "vkernels".                     
   1.7.  What is the latest version of FreeBSD?                               
         At any point in the development of FreeBSD, there can be multiple    
         parallel branches. 9.X releases are made from the 9-STABLE branch,   
         and 8.X releases are made from the 8-STABLE branch.                  
                                                                              
         Up until the release of 9.0, the 8.X series was the one known as     
         -STABLE. However, as of 10.X, the 8.X branch will be designated for  
         an "extended support" status and receive only fixes for major        
         problems, such as security-related fixes.                            
                                                                              
         Version 9.2 is the latest release from the 9-STABLE branch; it was   
         released in September 2013. Version 8.4 is the latest release from   
         the 8-STABLE branch; it was released in June 2013.                   
                                                                              
         Briefly, -STABLE is aimed at the ISP, corporate user, or any user    
         who wants stability and a minimal number of changes compared to the  
         new (and possibly unstable) features of the latest -CURRENT          
         snapshot. Releases can come from either branch, but -CURRENT should  
         only be used if you are prepared for its increased volatility        
         (relative to -STABLE, that is).                                      
                                                                              
         Releases are made every few months. While many people stay more      
         up-to-date with the FreeBSD sources (see the questions on            
         FreeBSD-CURRENT and FreeBSD-STABLE) than that, doing so is more of a 
         commitment, as the sources are a moving target.                      
                                                                              
         More information on FreeBSD releases can be found on the Release     
         Engineering page and in release(7).                                  
   1.8.  What is FreeBSD-CURRENT?                                             
         FreeBSD-CURRENT is the development version of the operating system,  
         which will in due course become the new FreeBSD-STABLE branch. As    
         such, it is really only of interest to developers working on the     
         system and die-hard hobbyists. See the relevant section in the       
         Handbook for details on running -CURRENT.                            
                                                                              
         If you are not familiar with FreeBSD you should not use              
         FreeBSD-CURRENT. This branch sometimes evolves quite quickly and due 
         to mistake can be un-buildable at times. People that use             
         FreeBSD-CURRENT are expected to be able to analyze, debug, and       
         report problems.                                                     
                                                                              
         FreeBSD snapshot releases are made based on the current state of the 
         -CURRENT and -STABLE branches. The goals behind each snapshot        
         release are:                                                         
                                                                              
           * To test the latest version of the installation software.         
                                                                              
           * To give people who would like to run -CURRENT or -STABLE but who 
             do not have the time or bandwidth to follow it on a day-to-day   
             basis an easy way of bootstrapping it onto their systems.        
                                                                              
           * To preserve a fixed reference point for the code in question,    
             just in case we break something really badly later. (Although    
             Subversion normally prevents anything horrible like this         
             happening.)                                                      
                                                                              
           * To ensure that all new features and fixes in need of testing     
             have the greatest possible number of potential testers.          
                                                                              
         No claims are made that any -CURRENT snapshot can be considered      
         "production quality" for any purpose. If you want to run a stable    
         and fully tested system, you will have to stick to full releases, or 
         use the -STABLE snapshots.                                           
                                                                              
         Snapshot releases are directly available from snapshot.              
                                                                              
         Official snapshots are generated on a regular basis for all actively 
         developed branches.                                                  
   1.9.  What is the FreeBSD-STABLE concept?                                  
         Back when FreeBSD 2.0.5 was released, FreeBSD development branched   
         in two. One branch was named -STABLE, one -CURRENT. FreeBSD-STABLE   
         is intended for Internet Service Providers and other commercial      
         enterprises for whom sudden shifts or experimental features are      
         quite undesirable. It receives only well-tested bug fixes and other  
         small incremental enhancements. FreeBSD-CURRENT, on the other hand,  
         has been one unbroken line since 2.0 was released, leading towards   
         9.2-RELEASE and beyond. For more detailed information on branches    
         see "FreeBSD Release Engineering: Creating the Release Branch", the  
         status of the branches and the upcoming release schedule can be      
         found on the Release Engineering Information page.                   
                                                                              
         9.2-STABLE is the actively developed -STABLE branch. The latest      
         release on the 9.2-STABLE branch is 9.2-RELEASE, which was released  
         in September 2013.                                                   
                                                                              
         The 10-CURRENT branch is the actively developed -CURRENT branch      
         toward the next generation of FreeBSD. See What is FreeBSD-CURRENT?  
         for more information on this branch.                                 
   1.10. When are FreeBSD releases made?                                      
         The re@FreeBSD.org releases a new major version of FreeBSD about     
         every 18 months and a new minor version about every 8 months, on     
         average. Release dates are announced well in advance, so that the    
         people working on the system know when their projects need to be     
         finished and tested. A testing period precedes each release, to      
         ensure that the addition of new features does not compromise the     
         stability of the release. Many users regard this caution as one of   
         the best things about FreeBSD, even though waiting for all the       
         latest goodies to reach -STABLE can be a little frustrating.         
                                                                              
         More information on the release engineering process (including a     
         schedule of upcoming releases) can be found on the release           
         engineering pages on the FreeBSD Web site.                           
                                                                              
         For people who need or want a little more excitement, binary         
         snapshots are made weekly as discussed above.                        
   1.11. Who is responsible for FreeBSD?                                      
         The key decisions concerning the FreeBSD project, such as the        
         overall direction of the project and who is allowed to add code to   
         the source tree, are made by a core team of 9 people. There is a     
         much larger team of more than 350 committers who are authorized to   
         make changes directly to the FreeBSD source tree.                    
                                                                              
         However, most non-trivial changes are discussed in advance in the    
         mailing lists, and there are no restrictions on who may take part in 
         the discussion.                                                      
   1.12. Where can I get FreeBSD?                                             
         Every significant release of FreeBSD is available via anonymous FTP  
         from the FreeBSD FTP site:                                           
                                                                              
           * The latest 9-STABLE release, 9.2-RELEASE can be found in the     
             9.2-RELEASE directory.                                           
                                                                              
           * Snapshot releases are made monthly for the -CURRENT and -STABLE  
             branch, these being of service purely to bleeding-edge testers   
             and developers.                                                  
                                                                              
           * The latest 8-STABLE release, 8.4-RELEASE can be found in the     
             8.4-RELEASE directory.                                           
                                                                              
         Information about obtaining FreeBSD on CD, DVD, and other media can  
         be found in the Handbook.                                            
   1.13. How do I access the Problem Report database?                         
         The Problem Report database of all user change requests may be       
         queried by using our web-based PR query interface.                   
                                                                              
         The send-pr(1) command can be used to submit problem reports and     
         change requests via electronic mail. Alternatively, the web-based    
         problem report submission interface can be used to submit problem    
         reports through a web browser.                                       
                                                                              
         Before submitting a problem report, please read Writing FreeBSD      
         Problem Reports, an article on how to write good problem reports.    

                      Chapter 2. Documentation and Support

   2.1. What good books are there about FreeBSD?

   2.2. Is the documentation available in other formats, such as plain text
   (ASCII), or PostScript(R)?

   2.3. Where do I find info on the FreeBSD mailing lists? What FreeBSD news
   groups are available?

   2.4. Are there FreeBSD IRC (Internet Relay Chat) channels?

   2.5. Are there any web based forums to discuss FreeBSD?

   2.6. Where can I get commercial FreeBSD training and support?

2.1. What good books are there about FreeBSD?                                                        
     The project produces a wide range of documentation, available online from this link:            
     http://www.FreeBSD.org/docs.html. In addition, the Bibliography at the end of this FAQ, and the 
     one in the Handbook reference other recommended books.                                          
2.2. Is the documentation available in other formats, such as plain text (ASCII), or PostScript(R)?  
     Yes. The documentation is available in a number of different formats and compression schemes on 
     the FreeBSD FTP site, in the /pub/FreeBSD/doc/ directory.                                       
                                                                                                     
     The documentation is categorized in a number of different ways. These include:                  
                                                                                                     
       * The document's name, such as faq, or handbook.                                              
                                                                                                     
       * The document's language and encoding. These are based on the locale names you will find     
         under /usr/share/locale on your FreeBSD system. The current languages and encodings that we 
         have for documentation are as follows:                                                      
                                                                                                     
                       Name                                        Meaning                           
         en_US.ISO8859-1                  English (United States)                                    
         bn_BD.ISO10646-1                 Bengali or Bangla (Bangladesh)                             
         da_DK.ISO8859-1                  Danish (Denmark)                                           
         de_DE.ISO8859-1                  German (Germany)                                           
         el_GR.ISO8859-7                  Greek (Greece)                                             
         es_ES.ISO8859-1                  Spanish (Spain)                                            
         fr_FR.ISO8859-1                  French (France)                                            
         hu_HU.ISO8859-2                  Hungarian (Hungary)                                        
         it_IT.ISO8859-15                 Italian (Italy)                                            
         ja_JP.eucJP                      Japanese (Japan, EUC encoding)                             
         mn_MN.UTF-8                      Mongolian (Mongolia, UTF-8 encoding)                       
         nl_NL.ISO8859-1                  Dutch (Netherlands)                                        
         no_NO.ISO8859-1                  Norwegian (Norway)                                         
         pl_PL.ISO8859-2                  Polish (Poland)                                            
         pt_BR.ISO8859-1                  Portuguese (Brazil)                                        
         ru_RU.KOI8-R                     Russian (Russia, KOI8-R encoding)                          
         sr_YU.ISO8859-2                  Serbian (Serbia)                                           
         tr_TR.ISO8859-9                  Turkish (Turkey)                                           
         zh_CN.GB2312                     Simplified Chinese (China, GB2312 encoding)                
         zh_TW.Big5                       Traditional Chinese (Taiwan, Big5 encoding)                
                                                                                                     
       Note:                                                                                         
                                                                                                     
         Some documents may not be available in all languages.                                       
                                                                                                     
       * The document's format. We produce the documentation in a number of different output         
         formats. Each format has its own advantages and disadvantages. Some formats are better      
         suited for online reading, while others are meant to be aesthetically pleasing when printed 
         on paper. Having the documentation available in any of these formats ensures that our       
         readers will be able to read the parts they are interested in, either on their monitor, or  
         on paper after printing the documents. The currently available formats are:                 
                                                                                                     
                  Format                                        Meaning                              
         html-split                A collection of small, linked, HTML files.                        
         html                      One large HTML file containing the entire document                
         pdf                       Adobe's Portable Document Format                                  
         ps                        PostScript(R)                                                     
         rtf                       Microsoft's Rich Text Format                                      
         txt                       Plain text                                                        
                                                                                                     
       Note:                                                                                         
                                                                                                     
         Page numbers are not automatically updated when loading Rich Text Format into Word. Press   
         Ctrl+A, Ctrl+End, F9 after loading the document, to update the page numbers.                
                                                                                                     
       * The compression and packaging scheme.                                                       
                                                                                                     
           1. Where the format is html-split, the files are bundled up using tar(1). The resulting   
              .tar file is then compressed using the compression schemes detailed in the next point. 
                                                                                                     
           2. All the other formats generate one file, called type.format (i.e., article.pdf,        
              book.html, and so on).                                                                 
                                                                                                     
              These files are then compressed using either the zip or bz2 compression schemes.       
              tar(1) can be used to uncompress these files.                                          
                                                                                                     
              So the PostScript(R) version of the Handbook, compressed using bzip2 will be stored in 
              a file called book.ps.bz2 in the handbook/ directory.                                  
                                                                                                     
     After choosing the format and compression mechanism that you want to download, you will have to 
     download the compressed files yourself, uncompress them, and then copy the appropriate          
     documents into place.                                                                           
                                                                                                     
     For example, the split HTML version of the FAQ, compressed using bzip2(1), can be found in      
     doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2 To download and uncompress that file you  
     would have to do this:                                                                          
                                                                                                     
     # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2 
     # tar xvf book.html-split.tar.bz2                                                               
                                                                                                     
     If the file is compressed, tar will automatically detect the appropriate format and decompress  
     it correctly. You will be left with a collection of .html files. The main one is called         
     index.html, which will contain the table of contents, introductory material, and links to the   
     other parts of the document. You can then copy or move these to their final location as         
     necessary.                                                                                      
2.3. Where do I find info on the FreeBSD mailing lists? What FreeBSD news groups are available?      
     You can find full information in the Handbook entry on mailing-lists and the Handbook entry on  
     newsgroups.                                                                                     
2.4. Are there FreeBSD IRC (Internet Relay Chat) channels?                                           
     Yes, most major IRC networks host a FreeBSD chat channel:                                       
                                                                                                     
       * Channel #FreeBSDhelp on EFNet is a channel dedicated to helping FreeBSD users. They are     
         much more sympathetic to questions than #FreeBSD is.                                        
                                                                                                     
       * Channel #FreeBSD on Freenode is a general help channel with many users at any time. The     
         conversations have been known to run off-topic for a while, but priority is given to users  
         with FreeBSD questions. We are good about helping you understand the basics, referring to   
         the Handbook whenever possible, and directing you where to learn more about the topic you   
         need help with. We are a primarily English speaking channel, though we have users from all  
         over the world. If you would like to speak in your native language, try to ask the question 
         in English and then relocate to another channel ##freebsd-lang as appropriate.              
                                                                                                     
       * Channel #FreeBSD on DALNET is available at irc.dal.net in the US and irc.eu.dal.net in      
         Europe.                                                                                     
                                                                                                     
       * Channel #FreeBSD on UNDERNET is available at us.undernet.org in the US and eu.undernet.org  
         in Europe. Since it is a help channel, be prepared to read the documents you are referred   
         to.                                                                                         
                                                                                                     
       * Channel #FreeBSD on RUSNET is a russian-language oriented channel dedicated to helping      
         FreeBSD users. This is also good place for non-technical discussions.                       
                                                                                                     
       * Channel #bsdchat on Freenode is a Traditional-Chinese (UTF-8 encoding) language oriented    
         channel dedicated to helping FreeBSD users. This is also good place for non-technical       
         discussions.                                                                                
                                                                                                     
     The FreeBSD wiki has a good list of IRC channels.                                               
                                                                                                     
     Each of these channels are distinct and are not connected to each other. Their chat styles also 
     differ, so you may need to try each to find one suited to your chat style. As with all types of 
     IRC traffic, if you are easily offended or cannot deal with lots of young people (and more than 
     a few older ones) doing the verbal equivalent of jello wrestling, do not even bother with it.   
2.5. Are there any web based forums to discuss FreeBSD?                                              
     The official FreeBSD forums are located at http://forums.FreeBSD.org/.                          
2.6. Where can I get commercial FreeBSD training and support?                                        
     iXsystems, Inc., parent company of the FreeBSD Mall, provides commercial FreeBSD and PC-BSD     
     software support, in addition to FreeBSD development and tuning solutions.                      
                                                                                                     
     BSD Certification Group, Inc. provides system administration certifications for DragonFly BSD,  
     FreeBSD, NetBSD, OpenBSD. If you are interested in them, visit their site.                      
                                                                                                     
     Any other organizations providing training and support should contact the Project to be listed  
     here.                                                                                           

                            Chapter 3. Installation

   Nik Clayton

   3.1. Which platform should I download? I have a 64 bit capable Intel(R)
   CPU, but I only see amd64.

   3.2. Which file do I download to get FreeBSD?

   3.3. What do I do if the images do not fit on a single disk?

   3.4. Where are the instructions for installing FreeBSD?

   3.5. What do I need to run FreeBSD?

   3.6. How can I make my own custom release or install disk?

   3.7. Can Windows(R) co-exist with FreeBSD?

   3.8. Another operating system destroyed my Boot Manager. How do I get it
   back?

   3.9. I booted from my ATAPI CD-ROM, but the install program says no CD-ROM
   is found. Where did it go?

   3.10. Do I need to install the source?

   3.11. Do I need to build a kernel?

   3.12. Should I use DES, Blowfish, or MD5 passwords and how do I specify
   which form my users receive?

   3.13. What are the limits for memory?

   3.14. What are the limits for FFS file systems?

   3.15. Why do I get an error message, readin failed after compiling and
   booting a new kernel?

   3.16. Is there a tool to perform post-installation configuration tasks?

   3.1.  Which platform should I download? I have a 64 bit capable Intel(R)   
         CPU, but I only see amd64.                                           
         amd64 is the term FreeBSD uses for 64-bit compatible x86             
         architectures (also known as "x86-64" or "x64"). Most modern         
         computers should use amd64. Older hardware should use i386. If you   
         are installing on a non-x86-compatible architecture select the       
         platform which best matches the architecture you are using.          
   3.2.  Which file do I download to get FreeBSD?                             
         On the Getting FreeBSD page select [iso] next to the architecture    
         you want to use.                                                     
                                                                              
         Any of the following can be used:                                    
                                                                              
             file                           description                       
         disc1.iso    Contains enough to install FreeBSD and a minimal set of 
                      packages.                                               
         dvd1.iso     Similar to disc1.iso but with additional packages.      
         memstick.img A bootable image sufficient for writing to a USB stick. 
         bootonly.iso A minimal image that requires network access during     
                      installation to completely install FreeBSD.             
                                                                              
         pc98 users require these floppy images: floppies/boot.flp,           
         floppies/kern1.flp, floppies/kern2.flp, and floppies/mfsroot1.flp.   
         These images need to be written onto floppies by tools like dd(1).   
                                                                              
         Full instructions on this procedure and a little bit more about      
         installation issues in general can be found in the Handbook entry on 
         installing FreeBSD.                                                  
   3.3.  What do I do if the images do not fit on a single disk?              
         Common mistakes when preparing the boot media are:                   
                                                                              
           * Not downloading the image in binary mode when using FTP.         
                                                                              
             Some FTP clients default their transfer mode to ascii and        
             attempt to change any end-of-line characters received to match   
             the conventions used by the client's system. This will almost    
             invariably corrupt the boot image. Check the SHA-256 of the      
             downloaded boot image: if it is not exactly that on the server,  
             then the download process is suspect.                            
                                                                              
             To workaround: type binary at the FTP command prompt after       
             getting connected to the server and before starting the download 
             of the image.                                                    
                                                                              
           * Using the DOS copy command (or equivalent GUI tool) to transfer  
             the boot image to floppy.                                        
                                                                              
             Programs like copy will not work as the boot image has been      
             created to be booted into directly. The image has the complete   
             content of the floppy, track for track, and is not meant to be   
             placed on the floppy as a regular file. You have to transfer it  
             to the floppy "raw", using the low-level tools (e.g., fdimage or 
             rawrite) described in the installation guide to FreeBSD.         
   3.4.  Where are the instructions for installing FreeBSD?                   
         Installation instructions for versions since FreeBSD 9.0 can be      
         found at Handbook entry on installing FreeBSD. Older instructions    
         can be found in the legacy entry on installing FreeBSD.              
   3.5.  What do I need to run FreeBSD?                                       
         For FreeBSD you will need a 486 or better PC, with 64 MB or more of  
         RAM and at least 1 GB of hard disk space.                            
                                                                              
         See also Chapter 4, Hardware Compatibility.                          
   3.6.  How can I make my own custom release or install disk?                
         Customized FreeBSD installation media can be created by building a   
         custom release. Follow the instructions in the Release Engineering   
         article.                                                             
   3.7.  Can Windows(R) co-exist with FreeBSD?                                
         If Windows(R) is installed first, then yes. FreeBSD's boot manager   
         will then manage to boot Windows(R) and FreeBSD. If you install      
         Windows(R) second, it will boorishly overwrite your boot manager     
         without even asking. If that happens, see the next section.          
   3.8.  Another operating system destroyed my Boot Manager. How do I get it  
         back?                                                                
         This depends on what boot manager you have installed. The FreeBSD    
         boot selection menu (likely what you are using if you end up in this 
         situation) can be reinstalled using boot0cfg(8). For example, to     
         restore the boot menu onto the disk ada0:                            
                                                                              
         # boot0cfg -B ada0                                                   
                                                                              
         The non-interactive MBR bootloader can be installed using gpart(8):  
                                                                              
         # gpart bootcode -b /boot/mbr ada0                                   
                                                                              
         For more complex situations, including GPT disks, see gpart(8).      
   3.9.  I booted from my ATAPI CD-ROM, but the install program says no       
         CD-ROM is found. Where did it go?                                    
         The usual cause of this problem is a mis-configured CD-ROM drive.    
         Many PCs now ship with the CD-ROM as the slave device on the         
         secondary IDE controller, with no master device on that controller.  
         This is illegal according to the ATAPI specification, but Windows(R) 
         plays fast and loose with the specification, and the BIOS ignores it 
         when booting. This is why the BIOS was able to see the CD-ROM to     
         boot from it, but why FreeBSD cannot see it to complete the install. 
                                                                              
         Reconfigure your system so that the CD-ROM is either the master      
         device on the IDE controller it is attached to, or make sure that it 
         is the slave on an IDE controller that also has a master device.     
   3.10. Do I need to install the source?                                     
         In general, no. There is nothing in the base system which requires   
         the presence of the source to operate. Some ports, like              
         sysutils/lsof, will not build unless the source is installed. In     
         particular, if the port builds a kernel module or directly operates  
         on kernel structures, the source must be installed.                  
   3.11. Do I need to build a kernel?                                         
         Usually not. The supplied GENERIC kernel contains the drivers an     
         ordinary computer will need. freebsd-update(8), the FreeBSD binary   
         upgrade tool, cannot upgrade custom kernels, another reason to stick 
         with the GENERIC kernel when possible. For computers with very       
         limited RAM, such as embedded systems, it may be worthwhile to build 
         a smaller custom kernel containing just the required drivers.        
   3.12. Should I use DES, Blowfish, or MD5 passwords and how do I specify    
         which form my users receive?                                         
         FreeBSD 7 and 8 use MD5 password hashing by default. Recent versions 
         of FreeBSD use SHA512 by default. These are believed to be more      
         secure than the traditional UNIX(R) password format, which used a    
         scheme based on the DES algorithm. DES passwords are still available 
         if you need to share your password file with legacy operating        
         systems which still use the less secure password format. FreeBSD     
         also allows you to use the Blowfish and MD5 password formats. Which  
         password format to use for new passwords is controlled by the        
         passwd_format login capability in /etc/login.conf, which takes       
         values of des, blf (if these are available) or md5. See the          
         login.conf(5) manual page for more information about login           
         capabilities.                                                        
   3.13. What are the limits for memory?                                      
         Memory limits depend on the platform used. On a standard i386(TM)    
         install, the limit is 4 GB but more memory can be supported through  
         pae(4). See instructions for using 4 GB or more memory on i386(TM).  
                                                                              
         FreeBSD/pc98 has a limit of 4 GB memory, and PAE can not be used     
         with it. Other architectures supported by FreeBSD have much higher   
         theoretical limits on maximum memory (many terabytes).               
   3.14. What are the limits for FFS file systems?                            
         For FFS file systems, the maximum theoretical limit is 8 TB (2 G     
         blocks), or 16 TB for the default block size of 8 KB. In practice,   
         there is a soft limit of 1 TB, but with modifications file systems   
         with 4 TB are possible (and exist).                                  
                                                                              
         The maximum size of a single FFS file is approximately 1 G blocks,   
         or 4 TB with a block size of 4 KB.                                   
                                                                              
         Table 3.1. Maximum File Sizes                                        
                                                                              
         +-----------------------------------------+                          
         | FS Block Size |   Works   | Should Work |                          
         |---------------+-----------+-------------|                          
         | 4 KB          | > 4 GB    | 4 TB - 1    |                          
         |---------------+-----------+-------------|                          
         | 8 KB          | > 32 GB   | 32 TB - 1   |                          
         |---------------+-----------+-------------|                          
         | 16 KB         | > 128 GB  | 32 TB - 1   |                          
         |---------------+-----------+-------------|                          
         | 32 KB         | > 512 GB  | 64 TB - 1   |                          
         |---------------+-----------+-------------|                          
         | 64 KB         | > 2048 GB | 128 TB - 1  |                          
         +-----------------------------------------+                          
                                                                              
         When the FS block size is 4 KB, triple indirect blocks work and      
         everything should be limited by the maximum FS block number that can 
         be represented using triple indirect blocks (approx.                 
         10243 + 10242 + 1024), but everything is limited by a (wrong) limit  
         of 1 G - 1 on FS block numbers. The limit on FS block numbers should 
         be 2 G - 1. There are some bugs for FS block numbers near 2 G - 1,   
         but such block numbers are unreachable when the FS block size is     
         4 KB.                                                                
                                                                              
         For block sizes of 8 KB and larger, everything should be limited by  
         the 2 G - 1 limit on FS block numbers, but is actually limited by    
         the 1 G - 1 limit on FS block numbers. Using the correct limit of    
         2 G - 1 blocks does cause problems.                                  
   3.15. Why do I get an error message, readin failed after compiling and     
         booting a new kernel?                                                
         Because your world and kernel are out of sync. This is not           
         supported. Be sure you use make buildworld and make buildkernel to   
         update your kernel.                                                  
                                                                              
         You can boot by specifying the kernel directly at the second stage,  
         pressing any key when the | shows up before loader is started.       
   3.16. Is there a tool to perform post-installation configuration tasks?    
         Yes, head/ users can set WITH_BSDCONFIG in /etc/src.conf. Users of   
         9.X and higher may also install sysutils/bsdconfig.                  

                       Chapter 4. Hardware Compatibility

   Table of Contents

   4.1. General

   4.2. Architectures and Processors

   4.3. Hard Drives, Tape Drives, and CD and DVD Drives

   4.4. Keyboards and Mice

   4.5. Other Hardware

4.1. General

   4.1.1. I want to get a piece of hardware for my FreeBSD system. Which
   model/brand/type is best?

   4.1.2. Does FreeBSD support more than 4 GB of memory (RAM)? More than
   16 GB? More than 48 GB?

   4.1.3. Why does FreeBSD report less than 4 GB memory when installed on an
   i386(TM) machine?

   4.1.1. I want to get a piece of hardware for my FreeBSD system. Which      
          model/brand/type is best?                                           
          This is discussed continually on the FreeBSD mailing lists. Since   
          hardware changes so quickly, however, we expect this. We still      
          strongly recommend that you read through the Hardware Notes for     
          FreeBSD 9.2 or 8.4 and search the mailing list archives before      
          asking about the latest and greatest hardware. Chances are a        
          discussion about the type of hardware you are looking for took      
          place just last week.                                               
                                                                              
          If you are looking for a laptop, check the FreeBSD laptop computer  
          mailing list archives. Otherwise, you probably want the archives    
          for the FreeBSD general questions mailing list, or possibly a       
          specific mailing list for a particular hardware type.               
   4.1.2. Does FreeBSD support more than 4 GB of memory (RAM)? More than      
          16 GB? More than 48 GB?                                             
          Yes. FreeBSD as an operating system generally supports as much      
          physical memory (RAM) as the platform it is running on does. Keep   
          in mind that different platforms have different limits for memory;  
          for example i386(TM) without PAE supports at most 4 GB of memory    
          (and usually less than that because of PCI address space) and       
          i386(TM) with PAE supports at most 64 GB memory. AMD64 platforms    
          currently deployed support up to 1 TB of physical memory.           
   4.1.3. Why does FreeBSD report less than 4 GB memory when installed on an  
          i386(TM) machine?                                                   
          The total address space on i386(TM) machines is 32-bit, meaning     
          that at most 4 GB of memory is addressable (can be accessed).       
          Furthermore, some addresses in this range are reserved by hardware  
          for different purposes, for example for using and controlling PCI   
          devices, for accessing video memory, and so on. Therefore, the      
          total amount of memory usable by the operating system for its       
          kernel and applications is limited to significantly less than 4 GB. 
          Usually, 3.2 GB to 3.7 GB is the maximum usable physical memory in  
          this configuration.                                                 
                                                                              
          To access more than 3.2 GB to 3.7 GB of installed memory (meaning   
          up to 4 GB but also more than 4 GB), a special tweak called PAE     
          must be used. PAE stands for Physical Address Extension and is a    
          way for 32-bit x86 CPUs to address more than 4 GB of memory. It     
          remaps the memory that would otherwise be overlaid by address       
          reservations for hardware devices above the 4 GB range and uses it  
          as additional physical memory (see pae(4)). Using PAE has some      
          drawbacks; this mode of memory access is a little bit slower than   
          the normal (without PAE) mode and loadable modules (see kld(4)) are 
          not supported. This means all drivers must be compiled into the     
          kernel.                                                             
                                                                              
          The most common way to enable PAE is to build a new kernel with the 
          special ready-provided kernel configuration file called PAE, which  
          is already configured to build a safe kernel. Note that some        
          entries in this kernel configuration file are too conservative and  
          some drivers marked as unready to be used with PAE are actually     
          usable. A rule of thumb is that if the driver is usable on 64-bit   
          architectures (like AMD64), it is also usable with PAE. If you wish 
          to create your own kernel configuration file, you can enable PAE by 
          adding the following line to your configuration:                    
                                                                              
          options       PAE                                                   
                                                                              
          PAE is not much used nowadays because most new x86 hardware also    
          supports running in 64-bit mode, known as AMD64 or Intel(R) 64. It  
          has a much larger address space and does not need such tweaks.      
          FreeBSD supports AMD64 and it is recommended that this version of   
          FreeBSD be used instead of the i386(TM) version if 4 GB or more     
          memory is required.                                                 

4.2. Architectures and Processors

   4.2.1. Does FreeBSD support architectures other than the x86?

   4.2.2. Does FreeBSD support Symmetric Multiprocessing (SMP)?

   4.2.3. What is microcode? How do I install Intel(R) CPU microcode updates?

   4.2.1. Does FreeBSD support architectures other than the x86?              
          Yes. FreeBSD divides support into multiple tiers. Tier 1            
          architectures, such as i386 or amd64; are fully supported. Tiers 2  
          and 3 are supported on an if-possible basis. A full explanation of  
          the tier system is available in the Committer's Guide.              
                                                                              
          A complete list of supported architectures can be found on the      
          platforms page.                                                     
   4.2.2. Does FreeBSD support Symmetric Multiprocessing (SMP)?               
          FreeBSD supports symmetric multi-processor (SMP) on all             
          non-embedded platforms (e.g, i386, amd64, etc.). SMP is also        
          supported in arm and MIPS kernels, although some CPUs may not       
          support this. FreeBSD's SMP implementation uses fine-grained        
          locking, and performance scales nearly linearly with number of      
          CPUs.                                                               
                                                                              
          smp(4) has more details.                                            
   4.2.3. What is microcode? How do I install Intel(R) CPU microcode updates? 
          Microcode is a method of programmatically implementating hardware   
          level instructions. This allows for CPU bugs to be fixed without    
          replacing the on board chip.                                        
                                                                              
          Install sysutils/devcpu-data, then add:                             
                                                                              
          microcode_update_enable="YES"                                       
                                                                              
          to /etc/rc.conf                                                     

4.3. Hard Drives, Tape Drives, and CD and DVD Drives

   4.3.1. What kind of hard drives does FreeBSD support?

   4.3.2. Which SCSI or SAS controllers are supported?

   4.3.3. What types of tape drives are supported?

   4.3.4. Does FreeBSD support tape changers?

   4.3.5. Which CD-ROM drives are supported by FreeBSD?

   4.3.6. Which CD-RW drives are supported by FreeBSD?

   4.3.1. What kind of hard drives does FreeBSD support?                      
          FreeBSD supports EIDE, SATA, SCSI, and SAS drives (with a           
          compatible controller; see the next section), and all drives using  
          the original "Western Digital" interface (MFM, RLL, ESDI, and of    
          course IDE). A few ESDI controllers that use proprietary interfaces 
          may not work: stick to WD1002/3/6/7 interfaces and clones.          
   4.3.2. Which SCSI or SAS controllers are supported?                        
          See the complete list in the Hardware Notes for FreeBSD 9.2 or 8.4. 
   4.3.3. What types of tape drives are supported?                            
          FreeBSD supports all standard SCSI tape interfaces.                 
   4.3.4. Does FreeBSD support tape changers?                                 
          FreeBSD supports SCSI changers using the ch(4) device and the       
          chio(1) command. The details of how you actually control the        
          changer can be found in the chio(1) manual page.                    
                                                                              
          If you are not using AMANDA or some other product that already      
          understands changers, remember that they only know how to move a    
          tape from one point to another, so you need to keep track of which  
          slot a tape is in, and which slot the tape currently in the drive   
          needs to go back to.                                                
   4.3.5. Which CD-ROM drives are supported by FreeBSD?                       
          Any SCSI drive connected to a supported controller is supported.    
          Most ATAPI compatible IDE CD-ROMs are supported.                    
   4.3.6. Which CD-RW drives are supported by FreeBSD?                        
          FreeBSD supports any ATAPI-compatible IDE CD-R or CD-RW drive. See  
          burncd(8) for details.                                              
                                                                              
          FreeBSD also supports any SCSI CD-R or CD-RW drives. Install and    
          use cdrecord from the ports or packages system, and make sure that  
          you have the pass device compiled in your kernel.                   

4.4. Keyboards and Mice

   4.4.1. Is it possible to use a mouse in any way outside the X Window
   system?

   4.4.2. How do I cut and paste text with a mouse in the text console?

   4.4.3. My mouse has a fancy wheel and buttons. Can I use them in FreeBSD?

   4.4.4. How do I use my delete key in sh and csh?

   4.4.1. Is it possible to use a mouse in any way outside the X Window       
          system?                                                             
          If you are using the default console driver, syscons(4), you can    
          use a mouse pointer in text consoles to cut & paste text. Run the   
          mouse daemon, moused(8), and turn on the mouse pointer in the       
          virtual console:                                                    
                                                                              
          # moused -p /dev/xxxx -t yyyy                                       
          # vidcontrol -m on                                                  
                                                                              
          Where xxxx is the mouse device name and yyyy is a protocol type for 
          the mouse. The mouse daemon can automatically determine the         
          protocol type of most mice, except old serial mice. Specify the     
          auto protocol to invoke automatic detection. If automatic detection 
          does not work, see the moused(8) manual page for a list of          
          supported protocol types.                                           
                                                                              
          If you have a PS/2 mouse, just add moused_enable="YES" to           
          /etc/rc.conf to start the mouse daemon at boot-time. Additionally,  
          if you would like to use the mouse daemon on all virtual terminals  
          instead of just the console, add allscreens_flags="-m on" to        
          /etc/rc.conf.                                                       
                                                                              
          When the mouse daemon is running, access to the mouse must be       
          coordinated between the mouse daemon and other programs such as X   
          Windows. Refer to the FAQ Why does my mouse not work with X? for    
          more details on this issue.                                         
   4.4.2. How do I cut and paste text with a mouse in the text console?       
          It is not possible to remove data using the mouse. However, it is   
          possible to "copy and paste". Once you get the mouse daemon running 
          (see the previous question) hold down button 1 (left button) and    
          move the mouse to select a region of text. Then, press button 2     
          (middle button) to paste it at the text cursor. Pressing button 3   
          (right button) will "extend" the selected region of text.           
                                                                              
          If your mouse does not have a middle button, you may wish to        
          emulate one or remap buttons using mouse daemon options. See the    
          moused(8) manual page for details.                                  
   4.4.3. My mouse has a fancy wheel and buttons. Can I use them in FreeBSD?  
          The answer is, unfortunately, "It depends". These mice with         
          additional features require specialized driver in most cases.       
          Unless the mouse device driver or the user program has specific     
          support for the mouse, it will act just like a standard two, or     
          three button mouse.                                                 
                                                                              
          For the possible usage of wheels in the X Window environment, refer 
          to that section.                                                    
   4.4.4. How do I use my delete key in sh and csh?                           
          For the Bourne Shell, add the following lines to your .shrc. See    
          sh(1) and editrc(5).                                                
                                                                              
          bind ^? ed-delete-next-char # for console                           
          bind ^[[3~ ed-delete-next-char # for xterm                          
                                                                              
          For the C Shell, add the following lines to your .cshrc. See        
          csh(1).                                                             
                                                                              
          bindkey ^? delete-char # for console                                
          bindkey ^[[3~ delete-char # for xterm                               
                                                                              
          For more information, see this page.                                

4.5. Other Hardware

   4.5.1. Workarounds for no sound from my pcm(4) sound card?

   4.5.2. Does FreeBSD support power management on my laptop?

   4.5.1. Workarounds for no sound from my pcm(4) sound card?                 
          Some sound cards set their output volume to 0 at every boot. Run    
          the following command every time the machine boots:                 
                                                                              
          # mixer pcm 100 vol 100 cd 100                                      
   4.5.2. Does FreeBSD support power management on my laptop?                 
          FreeBSD supports the ACPI features found in modern hardware.        
          Further information can be found in acpi(4).                        

                           Chapter 5. Troubleshooting

   5.1. Why is FreeBSD finding the wrong amount of memory on i386(TM)
   hardware?

   5.2. Why do my programs occasionally die with Signal 11 errors?

   5.3. My system crashes with either Fatal trap 12: page fault in kernel
   mode, or panic:, and spits out a bunch of information. What should I do?

   5.4. Why do I get the error maxproc limit exceeded by uid %i, please see
   tuning(7) and login.conf(5)?

   5.5. Why does sendmail give me an error reading mail loops back to myself?

   5.6. Why do full screen applications on remote machines misbehave?

   5.7. Why does it take so long to connect to my computer via ssh or telnet?

   5.8. Why does file: table is full show up repeatedly in dmesg(8)?

   5.9. Why does the clock on my computer keep incorrect time?

   5.10. What does the error swap_pager: indefinite wait buffer: mean?

   5.11. What is a lock order reversal?

   5.12. What does Called ... with the following non-sleepable locks held
   mean?

   5.13. Why does buildworld/installworld die with the message touch: not
   found?

   5.1.  Why is FreeBSD finding the wrong amount of memory on i386(TM)        
         hardware?                                                            
         The most likely reason is the difference between physical memory     
         addresses and virtual addresses.                                     
                                                                              
         The convention for most PC hardware is to use the memory area        
         between 3.5 GB and 4 GB for a special purpose (usually for PCI).     
         This address space is used to access PCI hardware. As a result real, 
         physical memory can not be accessed by that address space.           
                                                                              
         What happens to the memory that should appear in that location is    
         dependent on your hardware. Unfortunately, some hardware does        
         nothing and the ability to use that last 500 MB of RAM is entirely   
         lost.                                                                
                                                                              
         Luckily, most hardware remaps the memory to a higher location so     
         that it can still be used. However, this can cause some confusion if 
         you watch the boot messages.                                         
                                                                              
         On a 32-bit version of FreeBSD, the memory appears lost, since it    
         will be remapped above 4 GB, which a 32-bit kernel is unable to      
         access. In this case, the solution is to build a PAE enabled kernel. 
         See the entry on memory limits and about different memory limits on  
         different platforms for more information.                            
                                                                              
         On a 64-bit version of FreeBSD, or when running a PAE-enabled        
         kernel, FreeBSD will correctly detect and remap the memory so it is  
         usable. During boot, however, it may seem as if FreeBSD is detecting 
         more memory than the system really has, due to the described         
         remapping. This is normal and the available memory will be corrected 
         as the boot process completes.                                       
   5.2.  Why do my programs occasionally die with Signal 11 errors?           
         Signal 11 errors are caused when your process has attempted to       
         access memory which the operating system has not granted it access   
         to. If something like this is happening at seemingly random          
         intervals then you need to start investigating things very           
         carefully.                                                           
                                                                              
         These problems can usually be attributed to either:                  
                                                                              
          1. If the problem is occurring only in a specific application that  
             you are developing yourself it is probably a bug in your code.   
                                                                              
          2. If it is a problem with part of the base FreeBSD system, it may  
             also be buggy code, but more often than not these problems are   
             found and fixed long before us general FAQ readers get to use    
             these bits of code (that is what -CURRENT is for).               
                                                                              
         In particular, a dead giveaway that this is not a FreeBSD bug is if  
         you see the problem when you are compiling a program, but the        
         activity that the compiler is carrying out changes each time.        
                                                                              
         For example, suppose you are running make buildworld, and the        
         compile fails while trying to compile ls.c into ls.o. If you then    
         run make buildworld again, and the compile fails in the same place   
         then this is a broken build - try updating your sources and try      
         again. If the compile fails elsewhere then this is almost certainly  
         hardware.                                                            
                                                                              
         What you should do:                                                  
                                                                              
         In the first case you can use a debugger e.g., gdb(1) to find the    
         point in the program which is attempting to access a bogus address   
         and then fix it.                                                     
                                                                              
         In the second case you need to verify that it is not your hardware   
         at fault.                                                            
                                                                              
         Common causes of this include:                                       
                                                                              
          1. Your hard disks might be overheating: Check the fans in your     
             case are still working, as your disk (and perhaps other hardware 
             might be overheating).                                           
                                                                              
          2. The processor running is overheating: This might be because the  
             processor has been overclocked, or the fan on the processor      
             might have died. In either case you need to ensure that you have 
             hardware running at what it is specified to run at, at least     
             while trying to solve this problem (in other words, clock it     
             back to the default settings.)                                   
                                                                              
             If you are overclocking then note that it is far cheaper to have 
             a slow system than a fried system that needs replacing! Also the 
             wider community is not often sympathetic to problems on          
             overclocked systems, whether you believe it is safe or not.      
                                                                              
          3. Dodgy memory: If you have multiple memory SIMMS/DIMMS installed  
             then pull them all out and try running the machine with each     
             SIMM or DIMM individually and narrow the problem down to either  
             the problematic DIMM/SIMM or perhaps even a combination.         
                                                                              
          4. Over-optimistic Motherboard settings: In your BIOS settings, and 
             some motherboard jumpers you have options to set various         
             timings, mostly the defaults will be sufficient, but sometimes,  
             setting the wait states on RAM too low, or setting the "RAM      
             Speed: Turbo" option, or similar in the BIOS will cause strange  
             behavior. A possible idea is to set to BIOS defaults, but it     
             might be worth noting down your settings first!                  
                                                                              
          5. Unclean or insufficient power to the motherboard. If you have    
             any unused I/O boards, hard disks, or CD-ROMs in your system,    
             try temporarily removing them or disconnecting the power cable   
             from them, to see if your power supply can manage a smaller      
             load. Or try another power supply, preferably one with a little  
             more power (for instance, if your current power supply is rated  
             at 250 Watts try one rated at 300 Watts).                        
                                                                              
         You should also read the SIG11 FAQ (listed below) which has          
         excellent explanations of all these problems, albeit from a Linux(R) 
         viewpoint. It also discusses how memory testing software or hardware 
         can still pass faulty memory.                                        
                                                                              
         Finally, if none of this has helped it is possible that you have     
         just found a bug in FreeBSD, and you should follow the instructions  
         to send a problem report.                                            
                                                                              
         There is an extensive FAQ on this at the SIG11 problem FAQ.          
   5.3.  My system crashes with either Fatal trap 12: page fault in kernel    
         mode, or panic:, and spits out a bunch of information. What should I 
         do?                                                                  
         The FreeBSD developers are very interested in these errors, but need 
         some more information than just the error you see. Copy your full    
         crash message. Then consult the FAQ section on kernel panics, build  
         a debugging kernel, and get a backtrace. This might sound difficult, 
         but you do not need any programming skills; you just have to follow  
         the instructions.                                                    
   5.4.  Why do I get the error maxproc limit exceeded by uid %i, please see  
         tuning(7) and login.conf(5)?                                         
         The FreeBSD kernel will only allow a certain number of processes to  
         exist at one time. The number is based on the kern.maxusers          
         sysctl(8) variable. kern.maxusers also affects various other         
         in-kernel limits, such as network buffers. If your machine is        
         heavily loaded, you probably want to increase kern.maxusers. This    
         will increase these other system limits in addition to the maximum   
         number of processes.                                                 
                                                                              
         To adjust your kern.maxusers value, see the File/Process Limits      
         section of the Handbook. (While that section refers to open files,   
         the same limits apply to processes.)                                 
                                                                              
         If your machine is lightly loaded, and you are simply running a very 
         large number of processes, you can adjust this with the kern.maxproc 
         tunable. If this tunable needs adjustment it needs to be defined in  
         /boot/loader.conf. The tunable will not get adjusted until the       
         system is rebooted. For more information about tuning tunables, see  
         loader.conf(5). If these processes are being run by a single user,   
         you will also need to adjust kern.maxprocperuid to be one less than  
         your new kern.maxproc value. (It must be at least one less because   
         one system program, init(8), must always be running.)                
   5.5.  Why does sendmail give me an error reading mail loops back to        
         myself?                                                              
         You can find a detailed answer for this question in the Handbook.    
   5.6.  Why do full screen applications on remote machines misbehave?        
         The remote machine may be setting your terminal type to something    
         other than the cons25 terminal type required by the FreeBSD console. 
                                                                              
         There are a number of possible work-arounds for this problem:        
                                                                              
           * After logging on to the remote machine, set your TERM shell      
             variable to ansi or sco if the remote machine knows about these  
             terminal types.                                                  
                                                                              
           * Use a VT100 emulator like screen at the FreeBSD console. screen  
             offers you the ability to run multiple concurrent sessions from  
             one terminal, and is a neat program in its own right. Each       
             screen window behaves like a VT100 terminal, so the TERM         
             variable at the remote end should be set to vt100.               
                                                                              
           * Install the cons25 terminal database entry on the remote         
             machine. The way to do this depends on the operating system on   
             the remote machine. The system administration manuals for the    
             remote system should be able to help you here.                   
                                                                              
           * Fire up an X server at the FreeBSD end and login to the remote   
             machine using an X based terminal emulator such as xterm or      
             rxvt. The TERM variable at the remote host should be set to      
             xterm or vt100.                                                  
   5.7.  Why does it take so long to connect to my computer via ssh or        
         telnet?                                                              
         The symptom: there is a long delay between the time the TCP          
         connection is established and the time when the client software asks 
         for a password (or, in telnet(1)'s case, when a login prompt         
         appears).                                                            
                                                                              
         The problem: more likely than not, the delay is caused by the server 
         software trying to resolve the client's IP address into a hostname.  
         Many servers, including the Telnet and SSH servers that come with    
         FreeBSD, do this to store the hostname in a log file for future      
         reference by the administrator.                                      
                                                                              
         The remedy: if the problem occurs whenever you connect from your     
         computer (the client) to any server, the problem is with the client; 
         likewise, if the problem only occurs when someone connects to your   
         computer (the server) the problem is with the server.                
                                                                              
         If the problem is with the client, the only remedy is to fix the DNS 
         so the server can resolve it. If this is on a local network,         
         consider it a server problem and keep reading; conversely, if this   
         is on the global Internet, you will most likely need to contact your 
         ISP and ask them to fix it for you.                                  
                                                                              
         If the problem is with the server, and this is on a local network,   
         you need to configure the server to be able to resolve               
         address-to-hostname queries for your local address range. See the    
         hosts(5) and named(8) manual pages for more information. If this is  
         on the global Internet, the problem may be that your server's        
         resolver is not functioning correctly. To check, try to look up      
         another host - say, www.yahoo.com. If it does not work, that is your 
         problem.                                                             
                                                                              
         Following a fresh install of FreeBSD, it is also possible that       
         domain and name server information is missing from /etc/resolv.conf. 
         This will often cause a delay in SSH, as the option UseDNS is set to 
         yes by default in /etc/ssh/sshd_config. If this is causing the       
         problem, you will either need to fill in the missing information in  
         /etc/resolv.conf or set UseDNS to no in sshd_config as a temporary   
         workaround.                                                          
   5.8.  Why does file: table is full show up repeatedly in dmesg(8)?         
         This error message indicates you have exhausted the number of        
         available file descriptors on your system. Please see the            
         kern.maxfiles section of the Tuning Kernel Limits section of the     
         Handbook for a discussion and solution.                              
   5.9.  Why does the clock on my computer keep incorrect time?               
         Your computer has two or more clocks, and FreeBSD has chosen to use  
         the wrong one.                                                       
                                                                              
         Run dmesg(8), and check for lines that contain Timecounter. The one  
         with the highest quality value that FreeBSD chose.                   
                                                                              
         # dmesg | grep Timecounter                                           
         Timecounter "i8254" frequency 1193182 Hz quality 0                   
         Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000            
         Timecounter "TSC" frequency 2998570050 Hz quality 800                
         Timecounters tick every 1.000 msec                                   
                                                                              
         You can confirm this by checking the kern.timecounter.hardware       
         sysctl(3).                                                           
                                                                              
         # sysctl kern.timecounter.hardware                                   
         kern.timecounter.hardware: ACPI-fast                                 
                                                                              
         It may be a broken ACPI timer. The simplest solution is to disable   
         the ACPI timer in /boot/loader.conf:                                 
                                                                              
         debug.acpi.disabled="timer"                                          
                                                                              
         Or the BIOS may modify the TSC clock-perhaps to change the speed of  
         the processor when running from batteries, or going into a power     
         saving mode, but FreeBSD is unaware of these adjustments, and        
         appears to gain or lose time.                                        
                                                                              
         In this example, the i8254 clock is also available, and can be       
         selected by writing its name to the kern.timecounter.hardware        
         sysctl(3).                                                           
                                                                              
         # sysctl kern.timecounter.hardware=i8254                             
         kern.timecounter.hardware: TSC -> i8254                              
                                                                              
         Your computer should now start keeping more accurate time.           
                                                                              
         To have this change automatically run at boot time, add the          
         following line to /etc/sysctl.conf:                                  
                                                                              
         kern.timecounter.hardware=i8254                                      
   5.10. What does the error swap_pager: indefinite wait buffer: mean?        
         This means that a process is trying to page memory to disk, and the  
         page attempt has hung trying to access the disk for more than 20     
         seconds. It might be caused by bad blocks on the disk drive, disk    
         wiring, cables, or any other disk I/O-related hardware. If the drive 
         itself is actually bad, you will also see disk errors in             
         /var/log/messages and in the output of dmesg. Otherwise, check your  
         cables and connections.                                              
   5.11. What is a lock order reversal?                                       
         The FreeBSD kernel uses a number of resource locks to arbitrate      
         contention for certain resources. When multiple kernel threads try   
         to obtain multiple resource locks, there's always the potential for  
         a deadlock, where two threads have each obtained one of the locks    
         and blocks forever waiting for the other thread to release one of    
         the other locks. This sort of locking problem can be avoided if all  
         threads obtain the locks in the same order.                          
                                                                              
         A run-time lock diagnostic system called witness(4), enabled in      
         FreeBSD-CURRENT and disabled by default for stable branches and      
         releases, detects the potential for deadlocks due to locking errors, 
         including errors caused by obtaining multiple resource locks with a  
         different order from different parts of the kernel. The witness(4)   
         framework tries to detect this problem as it happens, and reports it 
         by printing a message to the system console about a lock order       
         reversal (often referred to also as LOR).                            
                                                                              
         It is possible to get false positives, as witness(4) is              
         conservative. A true positive report does not mean that a system is  
         dead-locked; instead it should be understood as a warning of the     
         form "if you were unlucky, a deadlock would have happened here".     
                                                                              
           Note:                                                              
                                                                              
         Problematic LORs tend to get fixed quickly, so check                 
         http://lists.FreeBSD.org/mailman/listinfo/freebsd-current before     
         posting to the mailing lists.                                        
   5.12. What does Called ... with the following non-sleepable locks held     
         mean?                                                                
         This means that a function that may sleep was called while a mutex   
         (or other unsleepable) lock was held.                                
                                                                              
         The reason this is an error is because mutexes are not intended to   
         be held for long periods of time; they are supposed to only be held  
         to maintain short periods of synchronization. This programming       
         contract allows device drivers to use mutexes to synchronize with    
         the rest of the kernel during interrupts. Interrupts (under FreeBSD) 
         may not sleep. Hence it is imperative that no subsystem in the       
         kernel block for an extended period while holding a mutex.           
                                                                              
         To catch such errors, assertions may be added to the kernel that     
         interact with the witness(4) subsystem to emit a warning or fatal    
         error (depending on the system configuration) when a potentially     
         blocking call is made while holding a mutex.                         
                                                                              
         In summary, such warnings are non-fatal, however with unfortunate    
         timing they could cause undesirable effects ranging from a minor     
         blip in the system's responsiveness to a complete system lockup.     
                                                                              
         For additional information about locking in FreeBSD see locking(9).  
   5.13. Why does buildworld/installworld die with the message touch: not     
         found?                                                               
         This error does not mean that the touch(1) utility is missing. The   
         error is instead probably due to the dates of the files being set    
         sometime in the future. If your CMOS-clock is set to local time you  
         need to run the command adjkerntz -i to adjust the kernel clock when 
         booting into single user mode.                                       

                          Chapter 6. User Applications

   6.1. So, where are all the user applications?

   6.2. How do I download the Ports tree? Should I be using SVN?

   6.3. Does FreeBSD support Java(TM)?

   6.4. Why can I not build this port on my 8.X -, or 9.X -STABLE machine?

   6.5. I just tried to build INDEX using make index, and it failed. Why?

   6.6. I updated the sources, now how do I update my installed ports?

   6.7. Do I need to recompile every port each time I perform a major version
   update?

   6.8. Do I need to recompile every port each time I perform a minor version
   update?

   6.9. Why is /bin/sh so minimal? Why does FreeBSD not use bash or another
   shell?

   6.10. How do I create audio CDs from my MIDI files?

   6.11. Where can I get an Office Suite for FreeBSD?

   6.12. How can I convert from pkgng to the old package tools?

   6.1.  So, where are all the user applications?                             
         Please take a look at the ports page for info on software packages   
         ported to FreeBSD. The list currently tops 24,000 and is growing     
         daily, so come back to check often or subscribe to the FreeBSD       
         announcements mailing list for periodic updates on new entries.      
                                                                              
         Most ports should work on the 8.X, and 9.X branches. Each time a     
         FreeBSD release is made, a snapshot of the ports tree at the time of 
         release in also included in the ports/ directory.                    
                                                                              
         We also support the concept of a "package", essentially no more than 
         a compressed binary distribution with a little extra intelligence    
         embedded in it for doing whatever custom installation work is        
         required. A package can be installed and uninstalled again easily    
         without having to know the gory details of which files it includes.  
                                                                              
         Use pkg_add(1) on the specific package files you are interested in   
         installing. Package files can usually be identified by their .tbz    
         suffix and CD-ROM distribution people will have a packages/All       
         directory on their CD which contains such files. They can also be    
         downloaded over the net for various versions of FreeBSD at the       
         following locations:                                                 
                                                                              
         for 8.X -RELEASE/8-STABLE                                            
                                                                              
            ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-8-stable    
                                                                              
         for 9.X -RELEASE/9-STABLE                                            
                                                                              
            ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-9-stable    
                                                                              
         or your nearest local mirror site.                                   
                                                                              
         Note that all ports may not be available as packages since new ones  
         are constantly being added. It is always a good idea to check back   
         periodically to see which packages are available at the              
         ftp.FreeBSD.org master site.                                         
   6.2.  How do I download the Ports tree? Should I be using SVN?             
         Any of the methods listed here work:                                 
                                                                              
           * Use portsnap for most use cases.                                 
                                                                              
           * Use SVN directly if you need custom patches to the ports tree.   
                                                                              
           * Use CTM if you prefer getting patches by email (this is a rarer  
             use case).                                                       
                                                                              
         Any other method should be considered a legacy method. If you do not 
         already use them, do not start.                                      
   6.3.  Does FreeBSD support Java(TM)?                                       
         Yes. Please see http://www.FreeBSD.org/java/.                        
   6.4.  Why can I not build this port on my 8.X -, or 9.X -STABLE machine?   
         If you are running a FreeBSD version that lags significantly behind  
         -CURRENT or -STABLE, you may need to update your Ports Collection;   
         see the Keeping Up section of the Porter's Handbook for further      
         information on how to do this. If you are up to date, then someone   
         might have committed a change to the port which works for -CURRENT   
         but which broke the port for -STABLE. Please submit a bug report on  
         this with the send-pr(1) command, since the Ports Collection is      
         supposed to work for both the -CURRENT and -STABLE branches.         
   6.5.  I just tried to build INDEX using make index, and it failed. Why?    
         First, always make sure that you have a complete up-to-date Ports    
         Collection. Errors that affect building INDEX from an up-to-date     
         copy of the Ports Collection are high-visibility and are thus almost 
         always fixed immediately.                                            
                                                                              
         There are rare cases where INDEX will not build due to odd cases     
         involving WITH_* or WITHOUT_* variables being set in make.conf. If   
         you suspect that this is the case, please try to make INDEX with     
         those make variables turned off before reporting it to FreeBSD ports 
         mailing list.                                                        
   6.6.  I updated the sources, now how do I update my installed ports?       
         FreeBSD does not include a port upgrading tool, but it does have     
         some tools to make the upgrade process somewhat easier. You can also 
         install additional tools to simplify port handling, see the          
         Upgrading Ports section in the FreeBSD Handbook.                     
   6.7.  Do I need to recompile every port each time I perform a major        
         version update?                                                      
         By all means! While a recent system will run with software compiled  
         under an older release, you will end up with things randomly         
         crashing and failing to work once you start installing other ports   
         or updating a portion of what you already have.                      
                                                                              
         When the system is upgraded, various shared libraries, loadable      
         modules, and other parts of the system will be replaced with newer   
         versions. Applications linked against the older versions may fail to 
         start or, in other cases, fail to function properly.                 
                                                                              
         For more information, see the section on upgrades in the FreeBSD     
         Handbook.                                                            
   6.8.  Do I need to recompile every port each time I perform a minor        
         version update?                                                      
         In general, no. FreeBSD developers do their utmost to guarantee      
         binary compatibility across all releases with the same major version 
         number. Any exceptions will be documented in the Release Notes, and  
         advice given there should be followed.                               
   6.9.  Why is /bin/sh so minimal? Why does FreeBSD not use bash or another  
         shell?                                                               
         Many people need to write shell scripts which will be portable       
         across many systems. That is why POSIX(R) specifies the shell and    
         utility commands in great detail. Most scripts are written in Bourne 
         shell (sh(1)), and because several important programming interfaces  
         (make(1), system(3), popen(3), and analogues in higher-level         
         scripting languages like Perl and Tcl) are specified to use the      
         Bourne shell to interpret commands. Because the Bourne shell is so   
         often and widely used, it is important for it to be quick to start,  
         be deterministic in its behavior, and have a small memory footprint. 
                                                                              
         The existing implementation is our best effort at meeting as many of 
         these requirements simultaneously as we can. To keep /bin/sh small,  
         we have not provided many of the convenience features that other     
         shells have. That is why other more featureful shells like bash,     
         scsh, tcsh(1), and zsh are available. (You can compare for yourself  
         the memory utilization of all these shells by looking at the "VSZ"   
         and "RSS" columns in a ps -u listing.)                               
   6.10. How do I create audio CDs from my MIDI files?                        
         To create audio CDs from MIDI files, first install audio/timidity++  
         from ports then install manually the GUS patches set by Eric A.      
         Welsh, available at http://alleg.sourceforge.net/digmid.html. After  
         TiMidity++ has been installed properly, MIDI files may be converted  
         to WAV files with the following command line:                        
                                                                              
         % timidity -Ow -s 44100 -o /tmp/juke/01.wav 01.mid                   
                                                                              
         The WAV files can then be converted to other formats or burned onto  
         audio CDs, as described in the FreeBSD Handbook.                     
   6.11. Where can I get an Office Suite for FreeBSD?                         
         The open-source Apache OpenOffice and LibreOffice office suites work 
         natively on FreeBSD.                                                 
                                                                              
         FreeBSD also includes a variety of text editors, spreadsheets, and   
         drawing programs in the Ports Collection.                            
   6.12. How can I convert from pkgng to the old package tools?               
         Short answer: it is not possible.                                    
                                                                              
         Longer answer: if you have made any changes using pkg converting     
         back is non-trivial and requires lots of manual editing of internal  
         package database files. However, if you have just run pkg2ng then    
         you may remove /var/db/pkg/local.sqlite and extract                  
         /var/backups/pkgdb.bak.tbz.                                          

                        Chapter 7. Kernel Configuration

   7.1. I would like to customize my kernel. Is it difficult?

   7.2. Why is my kernel so big?

   7.3. Why does every kernel I try to build fail to compile, even GENERIC?

   7.4. How can I verify which scheduler is in use on a running system?

   7.5. What is kern.sched.quantum?

   7.1. I would like to customize my kernel. Is it difficult?                 
        Not at all! Check out the kernel config section of the Handbook.      
                                                                              
          Note:                                                               
                                                                              
        The new kernel will be installed to the /boot/kernel directory along  
        with its modules, while the old kernel and its modules will be moved  
        to the /boot/kernel.old directory, so if you make a mistake the next  
        time you play with your configuration you can boot the previous       
        version of your kernel.                                               
   7.2. Why is my kernel so big?                                              
        GENERIC kernels shipped with FreeBSD and later are compiled in debug  
        mode. Kernels built in debug mode contain many symbols in separate    
        files that are used for debugging, thus greatly increasing the size   
        of /boot/kernel/. Note that there will be little or no performance    
        loss from running a debug kernel, and it is useful to keep one around 
        in case of a system panic.                                            
                                                                              
        However, if you are running low on disk space, there are different    
        options to reduce the size of /boot/kernel/.                          
                                                                              
        If you do not want the symbol files to be installed, make sure you    
        have the following line present in /etc/src.conf:                     
                                                                              
        WITHOUT_KERNEL_SYMBOLS=yes                                            
                                                                              
        For more information see src.conf(5).                                 
                                                                              
        If you do not want to build a debug kernel, make sure that both of    
        the following are true:                                               
                                                                              
          * You do not have a line in your kernel configuration file that     
            reads:                                                            
                                                                              
         makeoptions DEBUG=-g                                                 
                                                                              
          * You are not running config(8) with -g.                            
                                                                              
        Either of the above settings will cause your kernel to be built in    
        debug mode. As long as you make sure you follow the steps above, you  
        can build your kernel normally.                                       
                                                                              
        If you want only the modules you use to be built and installed, make  
        sure you have a line like below in /etc/make.conf:                    
                                                                              
        MODULES_OVERRIDE= accf_http ipfw                                      
                                                                              
        Replace accf_httpd ipfw with a list of modules you need. Only these   
        modules will be built. This does not only reduce the size of the      
        kernel directory but also decreases the amount of time needed to      
        build your kernel. For more information see                           
        /usr/share/examples/etc/make.conf.                                    
                                                                              
        You can also remove unneeded devices from your kernel to further      
        reduce the size. See Q: 7.1 for more information.                     
                                                                              
        To put any of these options into effect you will have to build and    
        install your new kernel.                                              
                                                                              
        Most kernels (/boot/kernel/kernel) tend to be around 12 MB to 16 MB.  
   7.3. Why does every kernel I try to build fail to compile, even GENERIC?   
        There are a number of possible causes for this problem. They are, in  
        no particular order:                                                  
                                                                              
          * You are not using the make buildkernel and make installkernel     
            targets, and your source tree is different from the one used to   
            build the currently running system (e.g., you are compiling       
            9.2-RELEASE on a 8.4-RELEASE system). If you are attempting an    
            upgrade, please read /usr/src/UPDATING, paying particular         
            attention to the "COMMON ITEMS" section at the end.               
                                                                              
          * You are using the make buildkernel and make installkernel         
            targets, but you failed to assert the completion of the make      
            buildworld target. The make buildkernel target relies on files    
            generated by the make buildworld target to complete its job       
            correctly.                                                        
                                                                              
          * Even if you are trying to build FreeBSD-STABLE, it is possible    
            that you fetched the source tree at a time when it was either     
            being modified, or broken for other reasons; only releases are    
            absolutely guaranteed to be buildable, although FreeBSD-STABLE    
            builds fine the majority of the time. If you have not already     
            done so, try re-fetching the source tree and see if the problem   
            goes away. Try using a different server in case the one you are   
            using is having problems.                                         
   7.4. How can I verify which scheduler is in use on a running system?       
        The name of the scheduler currently being used is directly available  
        as the value of the kern.sched.name sysctl:                           
                                                                              
        % sysctl kern.sched.name                                              
        kern.sched.name: ULE                                                  
   7.5. What is kern.sched.quantum?                                           
        kern.sched.quantum is the maximum number of ticks a process can run   
        without being preempted in the 4BSD scheduler.                        

                Chapter 8. Disks, File Systems, and Boot Loaders

   Table of Contents

   8.1. ZFS

   8.1. How can I add my new hard disk to my FreeBSD system?

   8.2. How do I move my system over to my huge new disk?

   8.3. Which partitions can safely use Soft Updates? I have heard that Soft
   Updates on / can cause problems. What about Journaled Soft Updates?

   8.4. Can I mount other foreign file systems under FreeBSD?

   8.5. How do I mount a secondary DOS partition?

   8.6. Is there a cryptographic file system for FreeBSD?

   8.7. How can I use the Windows NT(R) loader to boot FreeBSD?

   8.8. How do I boot FreeBSD and Linux(R) from LILO?

   8.9. How do I boot FreeBSD and Linux(R) using GRUB?

   8.10. How do I boot FreeBSD and Linux(R) using BootEasy?

   8.11. How do I change the boot prompt from ??? to something more
   meaningful?

   8.12. I have a new removable drive, how do I use it?

   8.13. Why do I get Incorrect super block when mounting a CD-ROM?

   8.14. Why do I get Device not configured when mounting a CD-ROM?

   8.15. Why do all non-English characters in filenames show up as "?" on my
   CDs when mounted in FreeBSD?

   8.16. I burned a CD under FreeBSD and now I can not read it under any
   other operating system. Why?

   8.17. How can I create an image of a data CD?

   8.18. Why can I not mount an audio CD?

   8.19. How do I mount a multi-session CD?

   8.20. How do I let ordinary users mount CD-ROMs, DVDs, USB drives, and
   other removable media?

   8.21. The du and df commands show different amounts of disk space
   available. What is going on?

   8.22. How can I add more swap space?

   8.23. Why does FreeBSD see my disk as smaller than the manufacturer says
   it is?

   8.24. How is it possible for a partition to be more than 100% full?

   8.1.  How can I add my new hard disk to my FreeBSD system?                 
         See the Adding Disks section in the FreeBSD Handbook.                
   8.2.  How do I move my system over to my huge new disk?                    
         The best way is to reinstall the OS on the new disk, then move the   
         user data over. This is highly recommended if you have been tracking 
         -STABLE for more than one release, or have updated a release instead 
         of installing a new one. You can install booteasy on both disks with 
         boot0cfg(8), and dual boot them until you are happy with the new     
         configuration. Skip the next paragraph to find out how to move the   
         data after doing this.                                               
                                                                              
         Alternatively, partition and label the new disk with either sade(8)  
         or gpart(8). If the disks are MBR-formatted, you can also install    
         booteasy on both disks with boot0cfg(8), so that you can dual boot   
         to the old or new system after the copying is done.                  
                                                                              
         Now you have the new disk set up, and are ready to move the data.    
         Unfortunately, you cannot just blindly copy the data. Things like    
         device files (in /dev), flags, and links tend to screw that up. You  
         need to use tools that understand these things, which means dump(8). 
         Although it is suggested that you move the data in single user mode, 
         it is not required.                                                  
                                                                              
         You should never use anything but dump(8) and restore(8) to move the 
         root file system. The tar(1) command may work - then again, it may   
         not. You should also use dump(8) and restore(8) if you are moving a  
         single partition to another empty partition. The sequence of steps   
         to use dump to move a partitions data to a new partition is:         
                                                                              
          1. newfs the new partition.                                         
                                                                              
          2. mount it on a temporary mount point.                             
                                                                              
          3. cd to that directory.                                            
                                                                              
          4. dump the old partition, piping output to the new one.            
                                                                              
         For example, if you are going to move root to /dev/ada1s1a, with     
         /mnt as the temporary mount point, it is:                            
                                                                              
         # newfs /dev/ada1s1a                                                 
         # mount /dev/ada1s1a /mnt                                            
         # cd /mnt                                                            
         # dump 0af - / | restore rf -                                        
                                                                              
         Rearranging your partitions with dump takes a bit more work. To      
         merge a partition like /var into its parent, create the new          
         partition large enough for both, move the parent partition as        
         described above, then move the child partition into the empty        
         directory that the first move created:                               
                                                                              
         # newfs /dev/ada1s1a                                                 
         # mount /dev/ada1s1a /mnt                                            
         # cd /mnt                                                            
         # dump 0af - / | restore rf -                                        
         # cd var                                                             
         # dump 0af - /var | restore rf -                                     
                                                                              
         To split a directory from its parent, say putting /var on its own    
         partition when it was not before, create both partitions, then mount 
         the child partition on the appropriate directory in the temporary    
         mount point, then move the old single partition:                     
                                                                              
         # newfs /dev/ada1s1a                                                 
         # newfs /dev/ada1s1d                                                 
         # mount /dev/ada1s1a /mnt                                            
         # mkdir /mnt/var                                                     
         # mount /dev/ada1s1d /mnt/var                                        
         # cd /mnt                                                            
         # dump 0af - / | restore rf -                                        
                                                                              
         You might prefer cpio(1), pax(1), tar(1) to dump(8) for user data.   
         At the time of this writing, these are known to lose file flag       
         information, so use them with caution.                               
   8.3.  Which partitions can safely use Soft Updates? I have heard that Soft 
         Updates on / can cause problems. What about Journaled Soft Updates?  
         Short answer: you can usually use Soft Updates safely on all         
         partitions.                                                          
                                                                              
         Long answer: Soft Updates has two characteristics that may be        
         undesirable on certain paritions. First, a Soft Updates partition    
         has a small chance of losing data during a system crash. (The        
         partition will not be corrupted; the data will simply be lost.)      
         Second, Soft Updates can cause temporary space shortages.            
                                                                              
         When using Soft Updates, the kernel can take up to thirty seconds to 
         write changes to the physical disk. When a large file is deleted the 
         file still resides on disk until the kernel actually performs the    
         deletion. This can cause a very simple race condition. Suppose you   
         delete one large file and immediately create another large file. The 
         first large file is not yet actually removed from the physical disk, 
         so the disk might not have enough room for the second large file.    
         You get an error that the partition does not have enough space,      
         although you know perfectly well that you just released a large      
         chunk of space! When you try again mere seconds later, the file      
         creation works as you expect. This has left more than one user       
         scratching his head and doubting his sanity, the FreeBSD file        
         system, or both.                                                     
                                                                              
         If a system should crash after the kernel accepts a chunk of data    
         for writing to disk, but before that data is actually written out,   
         data could be lost. This risk is extremely small, but generally      
         manageable.                                                          
                                                                              
         These issues affect all partitions using Soft Updates. So, what does 
         this mean for the root partition?                                    
                                                                              
         Vital information on the root partition changes very rarely. If the  
         system crashed during the thirty-second window after such a change   
         is made, it is possible that data could be lost. This risk is        
         negligible for most applications, but you should be aware that it    
         exists. If your system cannot tolerate this much risk, do not use    
         Soft Updates on the root file system!                                
                                                                              
         / is traditionally one of the smallest partitions. If you put the    
         /tmp directory on / and you have a busy /tmp, you might see          
         intermittent space problems. Symlinking /tmp to /var/tmp will solve  
         this problem.                                                        
                                                                              
         Finally, dump(8) does not work in live mode (-L) on a filesystem,    
         with Journaled Soft Updates (SU+J).                                  
   8.4.  Can I mount other foreign file systems under FreeBSD?                
         FreeBSD supports a variety of other file systems.                    
                                                                              
         UFS                                                                  
                                                                              
            UFS CD-ROMs can be mounted directly on FreeBSD. Mounting disk     
            partitions from Digital UNIX and other systems that support UFS   
            may be more complex, depending on the details of the disk         
            partitioning for the operating system in question.                
                                                                              
         ext2/ext3                                                            
                                                                              
            FreeBSD supports ext2fs and ext3fs partitions. See ext2fs(5) for  
            more information.                                                 
                                                                              
         NTFS                                                                 
                                                                              
            FUSE based NTFS support is available as a port                    
            (sysutils/fusefs-ntfs). For more information see ntfs-3g.         
                                                                              
         FAT                                                                  
                                                                              
            FreeBSD includes a read-write FAT driver. For more information,   
            see mount_msdosfs(8).                                             
                                                                              
         ZFS                                                                  
                                                                              
            FreeBSD includes a port of Sun(TM)'s ZFS driver. The current      
            recommendation is to use it only on amd64 platforms with          
            sufficient memory. For more information, see zfs(8).              
                                                                              
         FreeBSD also supports network file systems such as NFS (see          
         mount_nfs(8)), NetWare (see mount_nwfs(8)), and Microsoft-style SMB  
         file systems (see mount_smbfs(8)). You can find ports based on FUSE  
         (sysutils/fusefs-kmod) for many other file systems.                  
   8.5.  How do I mount a secondary DOS partition?                            
         The secondary DOS partitions are found after all the primary         
         partitions. For example, if you have an "E" partition as the second  
         DOS partition on the second SCSI drive, there will be a device file  
         for "slice 5" in /dev, so simply mount it:                           
                                                                              
         # mount -t msdosfs /dev/da1s5 /dos/e                                 
   8.6.  Is there a cryptographic file system for FreeBSD?                    
         Yes. You can use either gbde(8) or geli(8), see the Encrypting Disk  
         Partitions section of the FreeBSD Handbook.                          
   8.7.  How can I use the Windows NT(R) loader to boot FreeBSD?              
         The general idea is that you copy the first sector of your native    
         root FreeBSD partition into a file in the DOS/Windows NT(R)          
         partition. Assuming you name that file something like                
         c:\bootsect.bsd (inspired by c:\bootsect.dos), you can then edit     
         c:\boot.ini to come up with something like this:                     
                                                                              
         [boot loader]                                                        
         timeout=30                                                           
         default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS                  
         [operating systems]                                                  
         multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows NT"             
         C:\BOOTSECT.BSD="FreeBSD"                                            
         C:\="DOS"                                                            
                                                                              
         If FreeBSD is installed on the same disk as the Windows NT(R) boot   
         partition simply copy /boot/boot1 to C:\BOOTSECT.BSD. However, if    
         FreeBSD is installed on a different disk /boot/boot1 will not work,  
         /boot/boot0 is needed.                                               
                                                                              
         /boot/boot0 needs to be installed using sysinstall(8) by selecting   
         the FreeBSD boot manager on the screen which asks if you wish to use 
         a boot manager. This is because /boot/boot0 has the partition table  
         area filled with NULL characters but sysinstall(8) copies the        
         partition table before copying /boot/boot0 to the MBR.               
                                                                              
           Warning:                                                           
                                                                              
         Do not simply copy /boot/boot0 instead of /boot/boot1; you will      
         overwrite your partition table and render your computer un-bootable! 
                                                                              
         When the FreeBSD boot manager runs it records the last OS booted by  
         setting the active flag on the partition table entry for that OS and 
         then writes the whole 512-bytes of itself back to the MBR so if you  
         just copy /boot/boot0 to C:\BOOTSECT.BSD then it writes an empty     
         partition table, with the active flag set on one entry, to the MBR.  
   8.8.  How do I boot FreeBSD and Linux(R) from LILO?                        
         If you have FreeBSD and Linux(R) on the same disk, just follow       
         LILO's installation instructions for booting a non-Linux(R)          
         operating system. Very briefly, these are:                           
                                                                              
         Boot Linux(R), and add the following lines to /etc/lilo.conf:        
                                                                              
         other=/dev/hda2                                                      
                 table=/dev/hda                                               
                 label=FreeBSD                                                
                                                                              
         (the above assumes that your FreeBSD slice is known to Linux(R) as   
         /dev/hda2; tailor to suit your setup). Then, run lilo as root and    
         you should be done.                                                  
                                                                              
         If FreeBSD resides on another disk, you need to add                  
         loader=/boot/chain.b to the LILO entry. For example:                 
                                                                              
         other=/dev/dab4                                                      
                 table=/dev/dab                                               
                 loader=/boot/chain.b                                         
                 label=FreeBSD                                                
                                                                              
         In some cases you may need to specify the BIOS drive number to the   
         FreeBSD boot loader to successfully boot off the second disk. For    
         example, if your FreeBSD SCSI disk is probed by BIOS as BIOS disk 1, 
         at the FreeBSD boot loader prompt you need to specify:               
                                                                              
         Boot: 1:da(0,a)/boot/kernel/kernel                                   
                                                                              
         You can configure boot(8) to automatically do this for you at boot   
         time.                                                                
                                                                              
         The Linux(R)+FreeBSD mini-HOWTO is a good reference for FreeBSD and  
         Linux(R) interoperability issues.                                    
   8.9.  How do I boot FreeBSD and Linux(R) using GRUB?                       
         Booting FreeBSD using GRUB is very simple. Just add the following to 
         your configuration file /boot/grub/menu.lst (or /boot/grub/grub.conf 
         in some systems, e.g., Red Hat Linux and its derivatives).           
                                                                              
         title FreeBSD 6.1                                                    
                 root (hd0,a)                                                 
                 kernel /boot/loader                                          
                                                                              
         Where hd0,a points to your root partition on the first disk. If you  
         need to specify which slice number should be used, use something     
         like this (hd0,2,a). By default, if the slice number is omitted,     
         GRUB searches the first slice which has a partition.                 
   8.10. How do I boot FreeBSD and Linux(R) using BootEasy?                   
         Install LILO at the start of your Linux(R) boot partition instead of 
         in the Master Boot Record. You can then boot LILO from BootEasy.     
                                                                              
         If you are running Windows(R) and Linux(R) this is recommended       
         anyway, to make it simpler to get Linux(R) booting again if you      
         should need to reinstall Windows(R) (which is a Jealous Operating    
         System, and will bear no other Operating Systems in the Master Boot  
         Record).                                                             
   8.11. How do I change the boot prompt from ??? to something more           
         meaningful?                                                          
         You can not do that with the standard boot manager without rewriting 
         it. There are a number of other boot managers in the sysutils ports  
         category that provide this functionality.                            
   8.12. I have a new removable drive, how do I use it?                       
         If the drive already has a file system on it, you can use a command  
         like this:                                                           
                                                                              
         # mount -t msdosfs /dev/da0s1 /mnt                                   
                                                                              
         If the drive will only be used with FreeBSD systems it is better     
         idea to stick a BSD file system on it, like UFS or ZFS. You will get 
         long filename support, at least a 2X improvement in performance, and 
         a lot more stability. If the drive will be used by other operating   
         systems a more portable choice, such as msdosfs, is better.          
                                                                              
         # dd if=/dev/zero of=/dev/da0 count=2                                
         # gpart create -s GPT /dev/da0                                       
         # gpart add -t freebsd-ufs /dev/da0                                  
                                                                              
         Finally, create a new file system:                                   
                                                                              
         # newfs /dev/da0p1                                                   
                                                                              
         and mount it:                                                        
                                                                              
         # mount /dev/da0s1 /mnt                                              
                                                                              
         It is a good idea to add a line to /etc/fstab (see fstab(5)) so you  
         can just type mount /mnt in the future:                              
                                                                              
         /dev/da0p1 /mnt ufs rw,noauto 0 0                                    
   8.13. Why do I get Incorrect super block when mounting a CD-ROM?           
         You have to tell mount(8) the type of the device that you want to    
         mount. This is described in the Handbook section on optical media,   
         specifically the section Using Data CDs.                             
   8.14. Why do I get Device not configured when mounting a CD-ROM?           
         This generally means that there is no CD-ROM in the CD-ROM drive, or 
         the drive is not visible on the bus. Please see the Using Data CDs   
         section of the Handbook for a detailed discussion of this issue.     
   8.15. Why do all non-English characters in filenames show up as "?" on my  
         CDs when mounted in FreeBSD?                                         
         Your CD-ROM probably uses the "Joliet" extension for storing         
         information about files and directories. This is discussed in the    
         Handbook chapter on creating and using CD-ROMs, specifically the     
         section on Using Data CD-ROMs.                                       
   8.16. I burned a CD under FreeBSD and now I can not read it under any      
         other operating system. Why?                                         
         You most likely burned a raw file to your CD, rather than creating   
         an ISO 9660 file system. Take a look at the Handbook chapter on      
         creating CD-ROMs, particularly the section on burning raw data CDs.  
   8.17. How can I create an image of a data CD?                              
         This is discussed in the Handbook section on duplicating data CDs.   
         For more on working with CD-ROMs, see the Creating CDs Section in    
         the Storage chapter in the Handbook.                                 
   8.18. Why can I not mount an audio CD?                                     
         If you try to mount an audio CD, you will get an error like cd9660:  
         /dev/acd0c: Invalid argument. This is because mount only works on    
         file systems. Audio CDs do not have file systems; they just have     
         data. You need a program that reads audio CDs, such as the           
         audio/xmcd port.                                                     
   8.19. How do I mount a multi-session CD?                                   
         By default, mount(8) will attempt to mount the last data track       
         (session) of a CD. If you would like to load an earlier session, you 
         must use the -s command line argument. Please see mount_cd9660(8)    
         for specific examples.                                               
   8.20. How do I let ordinary users mount CD-ROMs, DVDs, USB drives, and     
         other removable media?                                               
         As root set the sysctl variable vfs.usermount to 1.                  
                                                                              
         # sysctl vfs.usermount=1                                             
                                                                              
         To make this persist across reboots, add the line vfs.usermount=1 to 
         /etc/sysctl.conf so that it is reset at system boot time.            
                                                                              
         Users can only mount devices they have read permissions to. To allow 
         users to mount a device permissions must be set in /etc/devfs.conf.  
                                                                              
         For example, to allow users to mount the first USB drive add:        
                                                                              
         # Allow all users to mount a USB drive.                              
                     own       /dev/da0       root:operator                   
                     perm      /dev/da00       0666                           
                                                                              
         All users can now mount devices they could read onto a directory     
         that they own:                                                       
                                                                              
         % mkdir ~/my-mount-point                                             
         % mount -t msdosfs /dev/da0~/my-mount-point                          
                                                                              
         Unmounting the device is simple:                                     
                                                                              
         % umount ~/my-mount-point                                            
                                                                              
         Enabling vfs.usermount, however, has negative security implications. 
         A better way to access MS-DOS(R) formatted media is to use the       
         emulators/mtools package in the Ports Collection.                    
                                                                              
           Note:                                                              
                                                                              
         The device name used in the previous examples must be changed        
         according to your configuration.                                     
   8.21. The du and df commands show different amounts of disk space          
         available. What is going on?                                         
         You need to understand what du and df really do. du goes through the 
         directory tree, measures how large each file is, and presents the    
         totals. df just asks the file system how much space it has left.     
         They seem to be the same thing, but a file without a directory entry 
         will affect df but not du.                                           
                                                                              
         When a program is using a file, and you delete the file, the file is 
         not really removed from the file system until the program stops      
         using it. The file is immediately deleted from the directory         
         listing, however. You can see this easily enough with a program such 
         as more. Assume you have a file large enough that its presence       
         affects the output of du and df. (Since disks can be so large today, 
         this might be a very large file!) If you delete this file while      
         using more on it, more does not immediately choke and complain that  
         it cannot view the file. The entry is simply removed from the        
         directory so no other program or user can access it. du shows that   
         it is gone - it has walked the directory tree and the file is not    
         listed. df shows that it is still there, as the file system knows    
         that more is still using that space. Once you end the more session,  
         du and df will agree.                                                
                                                                              
         This situation is common on web servers. Many people set up a        
         FreeBSD web server and forget to rotate the log files. The access    
         log fills up /var. The new administrator deletes the file, but the   
         system still complains that the partition is full. Stopping and      
         restarting the web server program would free the file, allowing the  
         system to release the disk space. To prevent this from happening,    
         set up newsyslog(8).                                                 
                                                                              
         Note that Soft Updates can delay the freeing of disk space; you      
         might need to wait up to 30 seconds for the change to be visible!    
   8.22. How can I add more swap space?                                       
         In the Configuration and Tuning section of the Handbook, you will    
         find a section describing how to do this.                            
   8.23. Why does FreeBSD see my disk as smaller than the manufacturer says   
         it is?                                                               
         Disk manufacturers calculate gigabytes as a billion bytes each,      
         whereas FreeBSD calculates them as 1,073,741,824 bytes each. This    
         explains why, for example, FreeBSD's boot messages will report a     
         disk that supposedly has 80 GB as holding 76,319 MB.                 
                                                                              
         Also note that FreeBSD will (by default) reserve 8% of the disk      
         space.                                                               
   8.24. How is it possible for a partition to be more than 100% full?        
         A portion of each UFS partition (8%, by default) is reserved for use 
         by the operating system and the root user. df(1) does not count that 
         space when calculating the Capacity column, so it can exceed 100%.   
         Also, you will notice that the Blocks column is always greater than  
         the sum of the Used and Avail columns, usually by a factor of 8%.    
                                                                              
         For more details, look up -m in tunefs(8).                           

8.1. ZFS

   8.1.1. What is the minimum amount of RAM one should have to run ZFS?

   8.1.2. What is the ZIL and when does it get used?

   8.1.3. Do I need a SSD for ZIL?

   8.1.4. What is the L2ARC?

   8.1.5. Is enabling deduplication advisable?

   8.1.6. I can not delete or create files on my ZFS pool. How can I fix
   this?

   8.1.7. Does ZFS support TRIM for Solid State Drives?

   8.1.1. What is the minimum amount of RAM one should have to run ZFS?       
          A minimum of 4GB of RAM is required for comfortable usage, but      
          individual workloads can vary widely.                               
   8.1.2. What is the ZIL and when does it get used?                          
          The ZIL ((ZFS intent log) is a write log used to implement posix    
          write commitment semantics across crashes. Normally writes are      
          bundled up into transaction groups and written to disk when filled  
          ("Transaction Group Commit"). However syscalls like fsync(2)        
          require a commitment that the data is written to stable storage     
          before returning. The ZIL is needed for writes that have been       
          acknowledged as written but which are not yet on disk as part of a  
          transaction. The transaction groups are timestamped. In the event   
          of a crash the last valid timestamp is found and missing data is    
          merged in from the ZIL.                                             
   8.1.3. Do I need a SSD for ZIL?                                            
          By default, ZFS stores the ZIL in the pool with all the data. If    
          your application has a heavy write load, storing the ZIL in a       
          separate device that has very fast synchronous, sequential write    
          performance can improve overall system. For other workloads, a SSD  
          is unlikely to make much of an improvement.                         
   8.1.4. What is the L2ARC?                                                  
          The L2ARC is a read cache stored on a fast device such as an SSD.   
          This cache is not persisent across reboots. Note that RAM is used   
          as the first layer of cache and the L2ARC is only needed if there   
          is insufficient RAM.                                                
                                                                              
          L2ARC needs space in the ARC to index it. So, perversely, a working 
          set that fits perfectly in the ARC will not fit perfectly any more  
          if a L2ARC is used because part of the ARC is holding the L2ARC     
          index, pushing part of the working set into the L2ARC which is      
          slower than RAM.                                                    
   8.1.5. Is enabling deduplication advisable?                                
          Generally speaking, no.                                             
                                                                              
          Deduplication takes up a significant amount of RAM and may slow     
          down read and write disk access times. Unless one is storing data   
          that is very heavily duplicated (such as virtual machine images, or 
          user backups) it is possible that deduplication will do more harm   
          than good. Another consideration is the inability to revert         
          deduplication status. If data is written when deduplication is      
          enabled, disabling dedup will not cause those blocks which were     
          deduplicated to be replicated until they are next modified.         
                                                                              
          Deduplication can also lead to some unexpected situations. In       
          particular deleting files may become much slower.                   
   8.1.6. I can not delete or create files on my ZFS pool. How can I fix      
          this?                                                               
          This could happen because the pool is 100% full. ZFS requires space 
          on the disk to write transaction metadata. To restore the pool to a 
          usable state, truncate a file you want to delete.                   
                                                                              
          % truncate -s 0 unimportant-file                                    
                                                                              
          File truncation works because a new transaction is not started, new 
          spare blocks are created instead.                                   
                                                                              
            Note:                                                             
                                                                              
          On systems with additional ZFS dataset tuning, such as              
          deduplication, the space may not be immediately available           
   8.1.7. Does ZFS support TRIM for Solid State Drives?                       
          ZFS TRIM support was added to FreeBSD 10-CURRENT with revision      
          r240868. ZFS TRIM support is not yet available on the -STABLE       
          branches.                                                           
                                                                              
          ZFS TRIM is enabled by default, and can be turned off by adding     
          this line to /etc/sysctl.conf:                                      
                                                                              
          vfs.zfs.trim_disable=1                                              
                                                                              
            Note:                                                             
                                                                              
          ZFS TRIM may not work with all configurations, such as a ZFS        
          filesystem on a GELI-backed device.                                 

                        Chapter 9. System Administration

   9.1. Where are the system start-up configuration files?

   9.2. How do I add a user easily?

   9.3. Why do I keep getting messages like root: not found after editing
   /etc/crontab

   9.4. Why do I get the error, you are not in the correct group to su root
   when I try to su to root?

   9.5. I made a mistake in rc.conf, or another startup file, and now I
   cannot edit it because the file system is read-only. What should I do?

   9.6. Why am I having trouble setting up my printer?

   9.7. How can I correct the keyboard mappings for my system?

   9.8. Why can I not get user quotas to work properly?

   9.9. Does FreeBSD support System V IPC primitives?

   9.10. What other mail-server software can I use instead of sendmail?

   9.11. I have forgotten the root password! What do I do?

   9.12. How do I keep Control+Alt+Delete from rebooting the system?

   9.13. How do I reformat DOS text files to UNIX(R) ones?

   9.14. How do I kill processes by name?

   9.15. How do I re-read /etc/rc.conf and re-start /etc/rc without a reboot?

   9.16. I tried to update my system to the latest -STABLE, but got -BETAx,
   -RC or -PRERELEASE! What is going on?

   9.17. I tried to install a new kernel, and the chflags(1) failed. How do I
   get around this?

   9.18. I cannot change the time on my system by more than one second! How
   do I get around this?

   9.19. Why is rpc.statd using 256 MB of memory?

   9.20. Why can I not unset the schg file flag?

   9.21. Why does SSH authentication through .shosts not work by default in
   recent versions of FreeBSD?

   9.22. What is vnlru?

   9.23. What do the various memory states displayed by top mean?

   9.24. How much free memory is available?

   9.25. What is /var/empty? I can not delete it!

   9.26. I just changed /etc/newsyslog.conf. How can I check if it does what
   I expect?

   9.27. My time is wrong, how can I change the timezone?

   9.1.  Where are the system start-up configuration files?                   
         The primary configuration file is /etc/defaults/rc.conf (see         
         rc.conf(5)). System startup scripts such as /etc/rc and /etc/rc.d    
         (see rc(8)) just include this file. Do not edit this file! Instead,  
         if there is any entry in /etc/defaults/rc.conf that you want to      
         change, you should copy the line into /etc/rc.conf and change it     
         there.                                                               
                                                                              
         For example, if you wish to start named(8), the included DNS server, 
         all you need to do is:                                               
                                                                              
         # echo 'named_enable="YES"' >> /etc/rc.conf                          
                                                                              
         To start up local services, place shell scripts in the               
         /usr/local/etc/rc.d directory. These shell scripts should be set     
         executable, the default file mode is 555.                            
   9.2.  How do I add a user easily?                                          
         Use the adduser(8) command, or the pw(8) command for more            
         complicated situations.                                              
                                                                              
         To remove the user, use the rmuser(8) command or, if necessary,      
         pw(8).                                                               
   9.3.  Why do I keep getting messages like root: not found after editing    
         /etc/crontab                                                         
         This is normally caused by editing the system crontab (/etc/crontab) 
         and then using crontab(1) to install it:                             
                                                                              
         # crontab /etc/crontab                                               
                                                                              
         This is not the correct way to do things. The system crontab has a   
         different format to the per-user crontabs which crontab(1) updates   
         (the crontab(5) manual page explains the differences in more         
         detail).                                                             
                                                                              
         If this is what you did, the extra crontab is simply a copy of       
         /etc/crontab in the wrong format it. Delete it with the command:     
                                                                              
         # crontab -r                                                         
                                                                              
         Next time, when you edit /etc/crontab, you should not do anything to 
         inform cron(8) of the changes, since it will notice them             
         automatically.                                                       
                                                                              
         If you want something to be run once per day, week, or month, it is  
         probably better to add shell scripts /usr/local/etc/periodic, and    
         let the periodic(8) command run from the system cron schedule it     
         with the other periodic system tasks.                                
                                                                              
         The actual reason for the error is that the system crontab has an    
         extra field, specifying which user to run the command as. In the     
         default system crontab provided with FreeBSD, this is root for all   
         entries. When this crontab is used as the root user's crontab (which 
         is not the same as the system crontab), cron(8) assumes the string   
         root is the first word of the command to execute, but no such        
         command exists.                                                      
   9.4.  Why do I get the error, you are not in the correct group to su root  
         when I try to su to root?                                            
         This is a security feature. To su to root (or any other account with 
         superuser privileges), you must be in the wheel group. If this       
         feature were not there, anybody with an account on a system who also 
         found out root's password would be able to gain superuser level      
         access to the system. With this feature, this is not strictly true;  
         su(1) will prevent them from even trying to enter the password if    
         they are not in wheel.                                               
                                                                              
         To allow someone to su to root, simply put them in the wheel group.  
         Use pw(8) for this purpose.                                          
                                                                              
         # pw groupmod wheel -m lisa                                          
                                                                              
         The above example will add user lisa to the group wheel.             
   9.5.  I made a mistake in rc.conf, or another startup file, and now I      
         cannot edit it because the file system is read-only. What should I   
         do?                                                                  
         Restart the system using boot -s at the loader prompt to enter       
         Single User mode. When prompted for a shell pathname, simply press   
         Enter, and run mount -urw / to re-mount the root file system in      
         read/write mode. You may also need to run mount -a -t ufs to mount   
         the file system where your favorite editor is defined. If your       
         favorite editor is on a network file system, you will need to either 
         configure the network manually before you can mount network file     
         systems, or use an editor which resides on a local file system, such 
         as ed(1).                                                            
                                                                              
         If you intend to use a full screen editor such as vi(1) or emacs(1), 
         you may also need to run export TERM=xterm on FreeBSD 9.0+, or       
         export TERM=cons25 on FreeBSD 8.X so that these editors can load the 
         correct data from the termcap(5) database.                           
                                                                              
         Once you have performed these steps, you can edit /etc/rc.conf as    
         you usually would to fix the syntax error. The error message         
         displayed immediately after the kernel boot messages should tell you 
         the number of the line in the file which is at fault.                
   9.6.  Why am I having trouble setting up my printer?                       
         See the Handbook entry on printing. It should cover most of your     
         problem.                                                             
                                                                              
         Some printers require a host-based driver to do any kind of          
         printing. These so-called "WinPrinters" are not natively supported   
         by FreeBSD. If your printer does not work in DOS or Windows(R), it   
         is probably a WinPrinter. Your only hope of getting one of these to  
         work is to check if the print/pnm2ppa port supports it.              
   9.7.  How can I correct the keyboard mappings for my system?               
         Please see the Handbook section on using localization, specifically  
         the section on console setup.                                        
   9.8.  Why can I not get user quotas to work properly?                      
          1. It is possible that your kernel is not configured to use quotas. 
             If this is the case, you will need to add the following line to  
             your kernel configuration file and recompile:                    
                                                                              
          options QUOTA                                                       
                                                                              
             Please read the Handbook entry on quotas for full details.       
                                                                              
          2. Do not turn on quotas on /.                                      
                                                                              
          3. Put the quota file on the file system that the quotas are to be  
             enforced on, i.e.:                                               
                                                                              
                     File System                      Quota file              
             /usr                         /usr/admin/quotas                   
             /home                        /home/admin/quotas                  
             ...                          ...                                 
   9.9.  Does FreeBSD support System V IPC primitives?                        
         Yes, FreeBSD supports System V-style IPC, including shared memory,   
         messages and semaphores, in the GENERIC kernel. With a custom        
         kernel, support may be loaded with the sysvshm.ko, sysvsem.ko and    
         sysvmsg.ko kernel modules, or enabled in the custom kernel by adding 
         the following lines to your kernel config:                           
                                                                              
         options    SYSVSHM          # enable shared memory                   
         options    SYSVSEM          # enable for semaphores                  
         options    SYSVMSG          # enable for messaging                   
                                                                              
         Recompile and install your kernel.                                   
   9.10. What other mail-server software can I use instead of sendmail?       
         The sendmail server is the default mail-server software for FreeBSD, 
         but you can easily replace it with one of the other MTA (for         
         instance, an MTA installed from the ports).                          
                                                                              
         There are various alternative MTAs in the ports tree already, with   
         mail/exim, mail/postfix, mail/qmail, and mail/zmailer being some of  
         the most popular choices.                                            
                                                                              
         Diversity is nice, and the fact that you have many different         
         mail-servers to chose from is considered a good thing; therefore try 
         to avoid asking questions like "Is sendmail better than qmail?" in   
         the mailing lists. If you do feel like asking, first check the       
         mailing list archives. The advantages and disadvantages of each and  
         every one of the available MTAs have already been discussed a few    
         times.                                                               
   9.11. I have forgotten the root password! What do I do?                    
         Do not panic! Restart the system, type boot -s at the Boot: prompt   
         to enter Single User mode. At the question about the shell to use,   
         hit Enter. You will be dropped to a # prompt. Enter mount -urw / to  
         remount your root file system read/write, then run mount -a to       
         remount all the file systems. Run passwd root to change the root     
         password then run exit(1) to continue booting.                       
                                                                              
           Note:                                                              
                                                                              
         If you are still prompted to give the root password when entering    
         the Single User mode, it means that the console has been marked as   
         insecure in /etc/ttys. In this case it will be required to boot from 
         a FreeBSD installation disk, choose the Live CD or Shell at the      
         beginning of the install process and issue the commands mentioned    
         above. You will need to mount the specific partition in this case    
         and then chroot to it, i.e., replace mount -urw / by mount           
         /dev/ada0p1 /mnt; chroot /mnt for a system on ada0p1.                
                                                                              
           Note:                                                              
                                                                              
         If you cannot mount your root partition from Single User mode, it is 
         possible that the partitions are encrypted and it is impossible to   
         mount them without the access keys. Your chances depend on the       
         chosen implementation. For more information see the section about    
         encrypted disks in the FreeBSD Handbook.                             
   9.12. How do I keep Control+Alt+Delete from rebooting the system?          
         If you are using syscons(4) (the default console driver) build and   
         install a new kernel with the line in the configuration file:        
                                                                              
         options SC_DISABLE_REBOOT                                            
                                                                              
         This can also be done by setting the following sysctl(8) which does  
         not require a reboot or kernel recompile:                            
                                                                              
         # sysctl hw.syscons.kbd_reboot=0                                     
                                                                              
           Note:                                                              
                                                                              
         The above two methods are exclusive: The sysctl(8) does not exist if 
         you compile your kernel with the SC_DISABLE_REBOOT option.           
   9.13. How do I reformat DOS text files to UNIX(R) ones?                    
         Use this perl(1) command:                                            
                                                                              
         % perl -i.bak -npe 's/\r\n/\n/g' file(s)                             
                                                                              
         where file(s) is one or more files to process. The modification is   
         done in-place, with the original file stored with a .bak extension.  
                                                                              
         Alternatively you can use the tr(1) command:                         
                                                                              
         % tr -d '\r' < dos-text-file > unix-file                             
                                                                              
         dos-text-file is the file containing DOS text while unix-file will   
         contain the converted output. This can be quite a bit faster than    
         using perl.                                                          
                                                                              
         Yet another way to reformat DOS text files is to use the             
         converters/dosunix port from the Ports Collection. Consult its       
         documentation about the details.                                     
   9.14. How do I kill processes by name?                                     
         Use pkill(1).                                                        
   9.15. How do I re-read /etc/rc.conf and re-start /etc/rc without a reboot? 
         Go into single user mode and then back to multi user mode.           
                                                                              
         On the console do:                                                   
                                                                              
         # shutdown now                                                       
         (Note: without -r or -h)                                             
                                                                              
         # return                                                             
         # exit                                                               
   9.16. I tried to update my system to the latest -STABLE, but got -BETAx,   
         -RC or -PRERELEASE! What is going on?                                
         Short answer: it is just a name. RC stands for "Release Candidate".  
         It signifies that a release is imminent. In FreeBSD, -PRERELEASE is  
         typically synonymous with the code freeze before a release. (For     
         some releases, the -BETA label was used in the same way as           
         -PRERELEASE.)                                                        
                                                                              
         Long answer: FreeBSD derives its releases from one of two places.    
         Major, dot-zero, releases, such as 9.0-RELEASE are branched from the 
         head of the development stream, commonly referred to as -CURRENT.    
         Minor releases, such as 6.3-RELEASE or 5.2-RELEASE, have been        
         snapshots of the active -STABLE branch. Starting with 4.3-RELEASE,   
         each release also now has its own branch which can be tracked by     
         people requiring an extremely conservative rate of development       
         (typically only security advisories).                                
                                                                              
         When a release is about to be made, the branch from which it will be 
         derived from has to undergo a certain process. Part of this process  
         is a code freeze. When a code freeze is initiated, the name of the   
         branch is changed to reflect that it is about to become a release.   
         For example, if the branch used to be called 6.2-STABLE, its name    
         will be changed to 6.3-PRERELEASE to signify the code freeze and     
         signify that extra pre-release testing should be happening. Bug      
         fixes can still be committed to be part of the release. When the     
         source code is in shape for the release the name will be changed to  
         6.3-RC to signify that a release is about to be made from it. Once   
         in the RC stage, only the most critical bugs found can be fixed.     
         Once the release (6.3-RELEASE in this example) and release branch    
         have been made, the branch will be renamed to 6.3-STABLE.            
                                                                              
         For more information on version numbers and the various Subversion   
         branches, refer to the Release Engineering article.                  
   9.17. I tried to install a new kernel, and the chflags(1) failed. How do I 
         get around this?                                                     
         Short answer: You are probably at security level greater than 0.     
         Reboot directly to Single User mode to install the kernel.           
                                                                              
         Long answer: FreeBSD disallows changing system flags at security     
         levels greater than 0. You can check your security level with the    
         command:                                                             
                                                                              
         # sysctl kern.securelevel                                            
                                                                              
         You cannot lower the security level; you have to boot to Single Mode 
         to install the kernel, or change the security level in /etc/rc.conf  
         then reboot. See the init(8) manual page for details on securelevel, 
         and see /etc/defaults/rc.conf and the rc.conf(5) manual page for     
         more information on rc.conf.                                         
   9.18. I cannot change the time on my system by more than one second! How   
         do I get around this?                                                
         Short answer: You are probably at security level greater than 1.     
         Reboot directly to Single User mode to change the date.              
                                                                              
         Long answer: FreeBSD disallows changing the time by more that one    
         second at security levels greater than 1. You can check your         
         security level with the command:                                     
                                                                              
         # sysctl kern.securelevel                                            
                                                                              
         You cannot lower the security level; you have to boot to Single User 
         mode to change the date, or change the security level in             
         /etc/rc.conf then reboot. See the init(8) manual page for details on 
         securelevel, and see /etc/defaults/rc.conf and the rc.conf(5) manual 
         page for more information on rc.conf.                                
   9.19. Why is rpc.statd using 256 MB of memory?                             
         No, there is no memory leak, and it is not using 256 MB of memory.   
         For convenience, rpc.statd maps an obscene amount of memory into its 
         address space. There is nothing terribly wrong with this from a      
         technical standpoint; it just throws off things like top(1) and      
         ps(1).                                                               
                                                                              
         rpc.statd(8) maps its status file (resident on /var) into its        
         address space; to save worrying about remapping it later when it     
         needs to grow, it maps it with a generous size. This is very evident 
         from the source code, where one can see that the length argument to  
         mmap(2) is 0x10000000, or one sixteenth of the address space on an   
         IA32, or exactly 256 MB.                                             
   9.20. Why can I not unset the schg file flag?                              
         You are running at an elevated (i.e., greater than 0) securelevel.   
         Lower the securelevel and try again. For more information, see the   
         FAQ entry on securelevel and the init(8) manual page.                
   9.21. Why does SSH authentication through .shosts not work by default in   
         recent versions of FreeBSD?                                          
         The reason why .shosts authentication does not work by default in    
         more recent versions of FreeBSD is because ssh(1) is not installed   
         suid root by default. To "fix" this, you can do one of the           
         following:                                                           
                                                                              
           * As a permanent fix, set ENABLE_SUID_SSH to true in               
             /etc/make.conf then rebuild and reinstall ssh(1).                
                                                                              
           * As a temporary fix, change the mode on /usr/bin/ssh to 4555 by   
             running chmod 4555 /usr/bin/ssh as root.                         
   9.22. What is vnlru?                                                       
         vnlru flushes and frees vnodes when the system hits the              
         kern.maxvnodes limit. This kernel thread sits mostly idle, and only  
         activates if you have a huge amount of RAM and are accessing tens of 
         thousands of tiny files.                                             
   9.23. What do the various memory states displayed by top mean?             
           * Active: pages recently statistically used.                       
                                                                              
           * Inactive: pages recently statistically unused.                   
                                                                              
           * Cache: (most often) pages that have percolated from inactive to  
             a status where they maintain their data, but can often be        
             immediately reused (either with their old association, or reused 
             with a new association). There can be certain immediate          
             transitions from active to cache state if the page is known to   
             be clean (unmodified), but that transition is a matter of        
             policy, depending upon the algorithm choice of the VM system     
             maintainer.                                                      
                                                                              
           * Free: pages without data content, and can be immediately used in 
             certain circumstances where cache pages might be ineligible.     
             Free pages can be reused at interrupt or process state.          
                                                                              
           * Wired: pages that are fixed into memory, usually for kernel      
             purposes, but also sometimes for special use in processes.       
                                                                              
         Pages are most often written to disk (sort of a VM sync) when they   
         are in the inactive state, but active pages can also be synced. This 
         depends upon the CPU tracking of the modified bit being available,   
         and in certain situations there can be an advantage for a block of   
         VM pages to be synced, whether they are active or inactive. In most  
         common cases, it is best to think of the inactive queue to be a      
         queue of relatively unused pages that might or might not be in the   
         process of being written to disk. Cached pages are already synced,   
         not mapped, but available for immediate process use with their old   
         association or with a new association. Free pages are available at   
         interrupt level, but cached or free pages can be used at process     
         state for reuse. Cache pages are not adequately locked to be         
         available at interrupt level.                                        
                                                                              
         There are some other flags (e.g., busy flag or busy count) that      
         might modify some of the described rules.                            
   9.24. How much free memory is available?                                   
         There are a couple of kinds of "free memory". One kind is the amount 
         of memory immediately available without paging anything else out.    
         That is approximately the size of cache queue + size of free queue   
         (with a derating factor, depending upon system tuning). Another kind 
         of "free memory" is the total amount of VM space. That can be        
         complex, but is dependent upon the amount of swap space and memory.  
         Other kinds of "free memory" descriptions are also possible, but it  
         is relatively useless to define these, but rather it is important to 
         make sure that the paging rate is kept low, and to avoid running out 
         of swap space.                                                       
   9.25. What is /var/empty? I can not delete it!                             
         /var/empty is a directory that the sshd(8) program uses when         
         performing privilege separation. The /var/empty directory is empty,  
         owned by root and has the schg flag set.                             
                                                                              
         Although it is not recommended to delete this directory, to do so    
         you will need to unset the schg flag first. See the chflags(1)       
         manual page for more information (and bear in mind the answer to the 
         question on unsetting the schg flag).                                
   9.26. I just changed /etc/newsyslog.conf. How can I check if it does what  
         I expect?                                                            
         To see what newsyslog(8) will do use the following:                  
                                                                              
         % newsyslog -nrvv                                                    
   9.27. My time is wrong, how can I change the timezone?                     
         Use tzsetup(8).                                                      

              Chapter 10. The X Window System and Virtual Consoles

   10.1. What is the X Window System?

   10.2. I want to run Xorg, how do I go about it?

   10.3. I tried to run X, but I get a No devices detected. error when I type
   startx. What do I do now?

   10.4. Why does my mouse not work with X?

   10.5. My mouse has a fancy wheel. Can I use it in X?

   10.6. My laptop has a Synaptics touchpad. Can I use it in X?

   10.7. How do I use remote X displays?

   10.8. What is a virtual console and how do I make more?

   10.9. How do I access the virtual consoles from X?

   10.10. How do I start XDM on boot?

   10.11. Why do I get Couldn't open console when I run xconsole?

   10.12. Why does my PS/2 mouse misbehave under X?

   10.13. How do I reverse the mouse buttons?

   10.14. How do I install a splash screen and where do I find them?

   10.15. Can I use the Windows keys on my keyboard in X?

   10.16. How can I get 3D hardware acceleration for OpenGL(R)?

   10.1.  What is the X Window System?                                        
          The X Window System (commonly X11) is the most widely available     
          windowing system capable of running on UNIX(R) or UNIX(R) like      
          systems, including FreeBSD. The X.Org Foundation administers the X  
          protocol standards, with the current reference implementation,      
          version 11 release 7.7, so you will often see references shortened  
          to X11.                                                             
                                                                              
          Many implementations are available for different architectures and  
          operating systems. An implementation of the server-side code is     
          properly known as an X server.                                      
   10.2.  I want to run Xorg, how do I go about it?                           
          To install Xorg do one of the following:                            
                                                                              
          Use the x11/xorg meta-port, which builds and installs every Xorg    
          component.                                                          
                                                                              
          Use x11/xorg-minimal, which builds and installs only the necessary  
          Xorg components.                                                    
                                                                              
          Install Xorg from FreeBSD packages:                                 
                                                                              
          # pkg_add -r xorg                                                   
                                                                              
          or on systems using pkg:                                            
                                                                              
          # pkg install xorg                                                  
                                                                              
          After the installation of Xorg, follow the instructions from the    
          X11 Configuration section of the FreeBSD Handbook.                  
   10.3.  I tried to run X, but I get a No devices detected. error when I     
          type startx. What do I do now?                                      
          Your system is probably running at a raised securelevel. It is not  
          possible to start X at a raised securelevel because X requires      
          write access to io(4). For more information, see at the init(8)     
          manual page.                                                        
                                                                              
          There are two solutions to the problem: Set your securelevel back   
          down to zero (usually in /etc/rc.conf), or run xdm(1) (or an        
          alternative display manager) at boot time (before the securelevel   
          is raised).                                                         
                                                                              
          See Q: 10.10 for more information about running xdm(1) at boot      
          time.                                                               
   10.4.  Why does my mouse not work with X?                                  
          If you are using syscons(4) (the default console driver), you can   
          configure FreeBSD to support a mouse pointer on each virtual        
          screen. To avoid conflicting with X, syscons(4) supports a virtual  
          device called /dev/sysmouse. All mouse events received from the     
          real mouse device are written to the sysmouse(4) device via         
          moused(8). To use your mouse on one or more virtual consoles, and   
          use X, see Q: 4.4.1 and set up moused(8).                           
                                                                              
          Then edit /etc/X11/xorg.conf and make sure you have the following   
          lines:                                                              
                                                                              
          Section "InputDevice"                                               
             Option          "Protocol" "SysMouse"                            
             Option          "Device" "/dev/sysmouse"                         
          .....                                                               
                                                                              
          Starting with Xorg version 7.4, the InputDevice sections in         
          xorg.conf are ignored in favor of autodetected devices. To restore  
          the old behavior, add the following line to the ServerLayout or     
          ServerFlags section:                                                
                                                                              
          Option "AutoAddDevices" "false"                                     
                                                                              
          Some people prefer to use /dev/mouse under X. To make this work,    
          /dev/mouse should be linked to /dev/sysmouse (see sysmouse(4)) by   
          adding the following line to /etc/devfs.conf (see devfs.conf(5)):   
                                                                              
          link    sysmouse    mouse                                           
                                                                              
          This link can be created by restarting devfs(5) with the following  
          command (as root):                                                  
                                                                              
          # service devfs restart                                             
   10.5.  My mouse has a fancy wheel. Can I use it in X?                      
          Yes.                                                                
                                                                              
          You need to tell X that you have a 5 button mouse. To do this,      
          simply add the lines Buttons 5 and ZAxisMapping 4 5 to the          
          "InputDevice" section of /etc/X11/xorg.conf. For example, you might 
          have the following "InputDevice" section in /etc/X11/xorg.conf.     
                                                                              
          Example 10.1. "InputDevice" Section for Wheeled Mouse in Xorg       
          Configuration File                                                  
                                                                              
          Section "InputDevice"                                               
             Identifier      "Mouse1"                                         
             Driver          "mouse"                                          
             Option          "Protocol" "auto"                                
             Option          "Device" "/dev/sysmouse"                         
             Option          "Buttons" "5"                                    
             Option          "ZAxisMapping" "4 5"                             
          EndSection                                                          
                                                                              
          Example 10.2. ".emacs" Example for Naive Page Scrolling with        
          Wheeled Mouse (optional)                                            
                                                                              
          ;; wheel mouse                                                      
          (global-set-key [mouse-4] 'scroll-down)                             
          (global-set-key [mouse-5] 'scroll-up)                               
   10.6.  My laptop has a Synaptics touchpad. Can I use it in X?              
          Yes, you will have to configure a few things to make it work.       
                                                                              
          If you plan to use the Xorg synaptics driver you must remove        
          moused_enable from rc.conf. Xorg can not use the synaptics mouse if 
          the moused already sits on /dev/psm0.                               
                                                                              
          To enable synaptics in the psm(4) driver you need to add the        
          following into /boot/loader.conf:                                   
                                                                              
          hw.psm.synaptics_support="1"                                        
                                                                              
          You also need the following into xorg.conf:                         
                                                                              
          Section "InputDevice"                                               
          Identifier  "Touchpad0"                                             
          Driver      "synaptics"                                             
          Option      "Protocol" "psm"                                        
          Option      "Device" "/dev/psm0"                                    
          EndSection                                                          
                                                                              
          And be sure to add the following into the "ServerLayout" section:   
                                                                              
          InputDevice    "Touchpad0" "SendCoreEvents"                         
   10.7.  How do I use remote X displays?                                     
          For security reasons, the default setting is to not allow a machine 
          to remotely open a window.                                          
                                                                              
          To enable this feature, simply start X with the optional            
          -listen_tcp argument:                                               
                                                                              
          % startx -listen_tcp                                                
   10.8.  What is a virtual console and how do I make more?                   
          Virtual consoles, put simply, enable you to have several            
          simultaneous sessions on the same machine without doing anything    
          complicated like setting up a network or running X.                 
                                                                              
          When the system starts, it will display a login prompt on the       
          monitor after displaying all the boot messages. You can then type   
          in your login name and password and start working (or playing!) on  
          the first virtual console.                                          
                                                                              
          At some point, you will probably wish to start another session,     
          perhaps to look at documentation for a program you are running or   
          to read your mail while waiting for an FTP transfer to finish. Just 
          do Alt+F2 (hold down Alt and press F2), and you will find a login   
          prompt waiting for you on the second "virtual console"! When you    
          want to go back to the original session, do Alt+F1.                 
                                                                              
          The default FreeBSD installation has eight virtual consoles         
          enabled. Alt+F1, Alt+F2, Alt+F3, and so on will switch between      
          these virtual consoles.                                             
                                                                              
          To enable more of them, edit /etc/ttys (see ttys(5)) and add        
          entries for ttyv8 to ttyvc after the comment on "Virtual            
          terminals":                                                         
                                                                              
          # Edit the existing entry for ttyv8 in /etc/ttys and change         
          # "off" to "on".                                                    
          ttyv8   "/usr/libexec/getty Pc"         xterm  on secure            
          ttyv9   "/usr/libexec/getty Pc"         xterm  on secure            
          ttyva   "/usr/libexec/getty Pc"         xterm  on secure            
          ttyvb   "/usr/libexec/getty Pc"         xterm  on secure            
                                                                              
          Use as many or as few as you want. The more virtual terminals you   
          have, the more resources that are used; this can be important if    
          you have 8 MB RAM or less. You may also want to change the secure   
          to insecure.                                                        
                                                                              
            Note:                                                             
                                                                              
          Versions of FreeBSD prior to 9.0 used the " cons25" terminal type,  
          and not " xterm". Existing entries in /etc/ttys can be used on      
          which to base new additions.                                        
                                                                              
            Important:                                                        
                                                                              
          If you want to run an X server you must leave at least one virtual  
          terminal unused (or turned off) for it to use. That is to say that  
          if you want to have a login prompt pop up for all twelve of your    
          Alt-function keys, you are out of luck - you can only do this for   
          eleven of them if you also want to run an X server on the same      
          machine.                                                            
                                                                              
          The easiest way to disable a console is by turning it off. For      
          example, if you had the full 12 terminal allocation mentioned above 
          and you wanted to run X, you would change settings for virtual      
          terminal 12 from:                                                   
                                                                              
          ttyvb   "/usr/libexec/getty Pc"         xterm  on  secure           
                                                                              
          to:                                                                 
                                                                              
          ttyvb   "/usr/libexec/getty Pc"         xterm  off secure           
                                                                              
          If your keyboard has only ten function keys, you would end up with: 
                                                                              
          ttyv9   "/usr/libexec/getty Pc"         xterm  off secure           
          ttyva   "/usr/libexec/getty Pc"         xterm  off secure           
          ttyvb   "/usr/libexec/getty Pc"         xterm  off secure           
                                                                              
          (You could also just delete these lines.)                           
                                                                              
          Next, the easiest (and cleanest) way to activate the virtual        
          consoles is to reboot. However, if you really do not want to        
          reboot, you can just shut down the X Window system and execute (as  
          root):                                                              
                                                                              
          # kill -HUP 1                                                       
                                                                              
          It is imperative that you completely shut down X Window if it is    
          running, before running this command. If you do not, your system    
          will probably appear to hang or lock up after executing kill.       
   10.9.  How do I access the virtual consoles from X?                        
          Use Ctrl+Alt+Fn to switch back to a virtual console. Ctrl+Alt+F1    
          would return you to the first virtual console.                      
                                                                              
          Once you are back to a text console, you can then use Alt+Fn as     
          normal to move between them.                                        
                                                                              
          To return to the X session, you must switch to the virtual console  
          running X. If you invoked X from the command line, (e.g., using     
          startx) then the X session will attach to the next unused virtual   
          console, not the text console from which it was invoked. If you     
          have eight active virtual terminals then X will be running on the   
          ninth, and you would use Alt+F9 to return.                          
   10.10. How do I start XDM on boot?                                         
          There are two schools of thought on how to start xdm(1). One school 
          starts xdm from /etc/ttys (see ttys(5)) using the supplied example, 
          while the other simply runs xdm from rc.local (see rc(8)) or from   
          an X script in /usr/local/etc/rc.d. Both are equally valid, and one 
          may work in situations where the other does not. In both cases the  
          result is the same: X will pop up a graphical login prompt.         
                                                                              
          The ttys(5) method has the advantage of documenting which vty X     
          will start on and passing the responsibility of restarting the X    
          server on logout to init(8). The rc(8) method makes it easy to kill 
          xdm if there is a problem starting the X server.                    
                                                                              
          If loaded from rc(8), xdm should be started without any arguments   
          (i.e., as a daemon). xdm must start after getty(8) runs, or else    
          getty and xdm will conflict, locking out the console. The best way  
          around this is to have the script sleep 10 seconds or so then       
          launch xdm.                                                         
                                                                              
          If you are to start xdm from /etc/ttys, there still is a chance of  
          conflict between xdm and getty(8). One way to avoid this is to add  
          the vt number in /usr/local/lib/X11/xdm/Xservers                    
                                                                              
          :0 local /usr/local/bin/X vt4                                       
                                                                              
          The above example will direct the X server to run in /dev/ttyv3.    
          Note the number is offset by one. The X server counts the vty from  
          one, whereas the FreeBSD kernel numbers the vty from zero.          
   10.11. Why do I get Couldn't open console when I run xconsole?             
          If you start X with startx, the permissions on /dev/console will    
          not get changed, resulting in things like xterm -C and xconsole not 
          working.                                                            
                                                                              
          This is because of the way console permissions are set by default.  
          On a multi-user system, one does not necessarily want just any user 
          to be able to write on the system console. For users who are        
          logging directly onto a machine with a VTY, the fbtab(5) file       
          exists to solve such problems.                                      
                                                                              
          In a nutshell, make sure an uncommented line of the form is in      
          /etc/fbtab (see fbtab(5)):                                          
                                                                              
          /dev/ttyv0 0600 /dev/console                                        
                                                                              
          It will ensure that whomever logs in on /dev/ttyv0 will own the     
          console.                                                            
   10.12. Why does my PS/2 mouse misbehave under X?                           
          Your mouse and the mouse driver may have somewhat become out of     
          synchronization.                                                    
                                                                              
          In rare cases the driver may erroneously report synchronization     
          problem and you may see the kernel message:                         
                                                                              
          psmintr: out of sync (xxxx != yyyy)                                 
                                                                              
          and notice that your mouse does not work properly.                  
                                                                              
          If this happens, disable the synchronization check code by setting  
          the driver flags for the PS/2 mouse driver to 0x100. This can be    
          easiest achieved by adding                                          
                                                                              
          hint.psm.0.flags="0x100"                                            
                                                                              
          to /boot/loader.conf and rebooting.                                 
   10.13. How do I reverse the mouse buttons?                                 
          Run the command xmodmap -e "pointer = 3 2 1".                       
                                                                              
          You add the above command to .xinitrc or .xsession to make it       
          happen automatically.                                               
   10.14. How do I install a splash screen and where do I find them?          
          The detailed answer for this question can be found in the Boot Time 
          Splash Screens section of the FreeBSD Handbook.                     
   10.15. Can I use the Windows keys on my keyboard in X?                     
          Yes. All you need to do is use xmodmap(1) to define what function   
          you wish them to perform.                                           
                                                                              
          Assuming all "Windows" keyboards are standard then the keycodes for 
          these three keys are the following:                                 
                                                                              
            * 115 - Windows key, between the left-hand Ctrl and Alt keys      
                                                                              
            * 116 - Windows key, to the right of AltGr                        
                                                                              
            * 117 - Menu, to the left of the right-hand Ctrl                  
                                                                              
          To have the left Windows key print a comma, try this.               
                                                                              
          # xmodmap -e "keycode 115 = comma"                                  
                                                                              
          To have the Windows key-mappings enabled automatically every time   
          you start X either put the xmodmap commands in ~/.xinitrc or,       
          preferably, create a ~/.xmodmaprc and include the xmodmap options,  
          one per line, then add the following line to ~/.xinitrc:            
                                                                              
          xmodmap $HOME/.xmodmaprc                                            
                                                                              
          For example, you could map the 3 keys to be F13, F14, and F15,      
          respectively. This would make it easy to map them to useful         
          functions within applications or your window manager, as            
          demonstrated further down.                                          
                                                                              
          To do this put the following in ~/.xmodmaprc.                       
                                                                              
          keycode 115 = F13                                                   
          keycode 116 = F14                                                   
          keycode 117 = F15                                                   
                                                                              
          If you use the x11-wm/fvwm2 port, for example, you could map the    
          keys so that F13 iconifies (or de-iconifies) the window the cursor  
          is in, F14 brings the window the cursor is in to the front or, if   
          it is already at the front, pushes it to the back, and F15 pops up  
          the main Workplace (application) menu even if the cursor is not on  
          the desktop, which is useful if you do not have any part of the     
          desktop visible (and the logo on the key matches its                
          functionality).                                                     
                                                                              
          The following entries in ~/.fvwmrc implement the aforementioned     
          setup:                                                              
                                                                              
          Key F13        FTIWS    A        Iconify                            
          Key F14        FTIWS    A        RaiseLower                         
          Key F15        A        A        Menu Workplace Nop                 
   10.16. How can I get 3D hardware acceleration for OpenGL(R)?               
          The availability of 3D acceleration depends on the version of Xorg  
          that you are using and the type of video chip you have. If you have 
          an nVidia chip, you can use the binary drivers provided for FreeBSD 
          by installing one of the following ports:                           
                                                                              
            * The latest versions of nVidia cards are supported by the        
              x11/nvidia-driver port.                                         
                                                                              
            * nVidia cards like the GeForce2 MX/3/4 series are supported by   
              the 96XX series of drivers, available in the                    
              x11/nvidia-driver-96xx port.                                    
                                                                              
            * Even older cards, like GeForce and RIVA TNT are supported by    
              the 71XX series of drivers, available in the                    
              x11/nvidia-driver-71xx port.                                    
                                                                              
          nVidia provides detailed information on which card is supported by  
          which driver on their web site:                                     
          http://www.nvidia.com/object/IO_32667.html.                         
                                                                              
          For Matrox G200/G400, check the x11-servers/mga_hal port.           
                                                                              
          For ATI Rage 128 and Radeon see ati(4), r128(4) and radeon(4).      

                             Chapter 11. Networking

   11.1. Where can I get information on "diskless booting"?

   11.2. Can a FreeBSD box be used as a dedicated network router?

   11.3. Can I connect my Windows(R) box to the Internet via FreeBSD?

   11.4. Does FreeBSD support PPP?

   11.5. Does FreeBSD support NAT or Masquerading?

   11.6. How can I set up Ethernet aliases?

   11.7. Why can I not NFS-mount from a Linux(R) box?

   11.8. Why does mountd keep telling me it can't change attributes and that
   I have a bad exports list on my FreeBSD NFS server?

   11.9. How do I enable IP multicast support?

   11.10. Why do I have to use the FQDN for hosts on my site?

   11.11. Why do I get an error, Permission denied, for all networking
   operations?

   11.12. Why is my ipfw "fwd" rule to redirect a service to another machine
   not working?

   11.13. How can I redirect service requests from one machine to another?

   11.14. Where can I get a bandwidth management tool?

   11.15. Why do I get /dev/bpf0: device not configured?

   11.16. How do I mount a disk from a Windows(R) machine that is on my
   network, like smbmount in Linux(R)?

   11.17. What are these messages about: Limiting icmp/open port/closed port
   response in my log files?

   11.18. What are these arp: unknown hardware address format error messages?

   11.19. Why do I keep seeing messages like: 192.168.0.10 is on fxp1 but got
   reply from 00:15:17:67:cf:82 on rl0, and how do I disable it?

11.1.  Where can I get information on "diskless booting"?                            
       "Diskless booting" means that the FreeBSD box is booted over a network, and   
       reads the necessary files from a server instead of its hard disk. For full    
       details, please read the Handbook entry on diskless booting.                  
11.2.  Can a FreeBSD box be used as a dedicated network router?                      
       Yes. Please see the Handbook entry on advanced networking, specifically the   
       section on routing and gateways.                                              
11.3.  Can I connect my Windows(R) box to the Internet via FreeBSD?                  
       Typically, people who ask this question have two PCs at home, one with        
       FreeBSD and one with some version of Windows(R) the idea is to use the        
       FreeBSD box to connect to the Internet and then be able to access the         
       Internet from the Windows(R) box through the FreeBSD box. This is really just 
       a special case of the previous question and works perfectly well.             
                                                                                     
       Dialup users must use -nat and set gateway_enable to YES in /etc/rc.conf. For 
       more information, please see the ppp(8) manual page or the Handbook entry on  
       user PPP.                                                                     
                                                                                     
       If you are using kernel-mode PPP or have an Ethernet connection to the        
       Internet, you need to use natd(8). Please look at the natd section of the     
       Handbook for a tutorial.                                                      
11.4.  Does FreeBSD support PPP?                                                     
       Yes. ppp(8) provides support for both incoming and outgoing connections.      
                                                                                     
       For more information on how to use this, please see the Handbook chapter on   
       PPP.                                                                          
11.5.  Does FreeBSD support NAT or Masquerading?                                     
       Yes. If you want to use NAT over a user PPP connection, please see the        
       Handbook entry on user PPP. If you want to use NAT over some other sort of    
       network connection, please look at the natd section of the Handbook.          
11.6.  How can I set up Ethernet aliases?                                            
       If the alias is on the same subnet as an address already configured on the    
       interface, then add netmask 0xffffffff to your ifconfig(8) command-line, as   
       in the following:                                                             
                                                                                     
       # ifconfig ed0 alias 192.0.2.2 netmask 0xffffffff                             
                                                                                     
       Otherwise, just specify the network address and netmask as usual:             
                                                                                     
       # ifconfig ed0 alias 172.16.141.5 netmask 0xffffff00                          
                                                                                     
       You can read more about this in the FreeBSD Handbook.                         
11.7.  Why can I not NFS-mount from a Linux(R) box?                                  
       Some versions of the Linux(R) NFS code only accept mount requests from a      
       privileged port; try to issue the following command:                          
                                                                                     
       # mount -o -P linuxbox:/blah /mnt                                             
11.8.  Why does mountd keep telling me it can't change attributes and that I have a  
       bad exports list on my FreeBSD NFS server?                                    
       The most frequent problem is not understanding the correct format of          
       /etc/exports. Please review exports(5) and the NFS entry in the Handbook,     
       especially the section on configuring NFS.                                    
11.9.  How do I enable IP multicast support?                                         
       FreeBSD supports multicast host operations by default. If you want your box   
       to run as a multicast router, you need to recompile your kernel with the      
       MROUTING option and run mrouted(8). FreeBSD will start mrouted(8) at boot     
       time if the flag mrouted_enable is set to YES in /etc/rc.conf.                
                                                                                     
         Note:                                                                       
                                                                                     
       In recent FreeBSD releases, the mrouted(8) multicast routing daemon, the      
       map-mbone(8) and mrinfo(8) utilities have been removed from the base system.  
       These programs are now available in the FreeBSD Ports Collection as           
       net/mrouted.                                                                  
11.10. Why do I have to use the FQDN for hosts on my site?                           
       See the answer in the FreeBSD Handbook.                                       
11.11. Why do I get an error, Permission denied, for all networking operations?      
       If you have compiled your kernel with the IPFIREWALL option, you need to be   
       aware that the default policy is to deny all packets that are not explicitly  
       allowed.                                                                      
                                                                                     
       If you had unintentionally misconfigured your system for firewalling, you can 
       restore network operability by typing the following while logged in as root:  
                                                                                     
       # ipfw add 65534 allow all from any to any                                    
                                                                                     
       You can also set firewall_type="open" in /etc/rc.conf.                        
                                                                                     
       For further information on configuring a FreeBSD firewall, see the Handbook   
       chapter.                                                                      
11.12. Why is my ipfw "fwd" rule to redirect a service to another machine not        
       working?                                                                      
       Possibly because you want to do network address translation (NAT) and not     
       just forward packets. A "fwd" rule does exactly what it says; it forwards     
       packets. It does not actually change the data inside the packet. Say we have  
       a rule like:                                                                  
                                                                                     
       01000 fwd 10.0.0.1 from any to foo 21                                         
                                                                                     
       When a packet with a destination address of foo arrives at the machine with   
       this rule, the packet is forwarded to 10.0.0.1, but it still has the          
       destination address of foo! The destination address of the packet is not      
       changed to 10.0.0.1. Most machines would probably drop a packet that they     
       receive with a destination address that is not their own. Therefore, using a  
       "fwd" rule does not often work the way the user expects. This behavior is a   
       feature and not a bug.                                                        
                                                                                     
       See the FAQ about redirecting services, the natd(8) manual, or one of the     
       several port redirecting utilities in the Ports Collection for a correct way  
       to do this.                                                                   
11.13. How can I redirect service requests from one machine to another?              
       You can redirect FTP (and other service) request with the sysutils/socket     
       port. Simply replace the service's command line to call socket instead, like  
       so:                                                                           
                                                                                     
       ftp stream tcp nowait nobody /usr/local/bin/socket socket ftp.example.com ftp 
                                                                                     
       where ftp.example.com and ftp are the host and port to redirect to,           
       respectively.                                                                 
11.14. Where can I get a bandwidth management tool?                                  
       There are three bandwidth management tools available for FreeBSD. dummynet(4) 
       is integrated into FreeBSD as part of ipfw(4). ALTQ has been integrated into  
       FreeBSD as part of pf(4). Bandwidth Manager from Emerging Technologies is a   
       commercial product.                                                           
11.15. Why do I get /dev/bpf0: device not configured?                                
       You are running a program that requires the Berkeley Packet Filter (bpf(4)),  
       but it is not in your kernel. Add this to your kernel config file and build a 
       new kernel:                                                                   
                                                                                     
       device bpf        # Berkeley Packet Filter                                    
11.16. How do I mount a disk from a Windows(R) machine that is on my network, like   
       smbmount in Linux(R)?                                                         
       Use the SMBFS toolset. It includes a set of kernel modifications and a set of 
       userland programs. The programs and information are available as              
       mount_smbfs(8) in the base system.                                            
11.17. What are these messages about: Limiting icmp/open port/closed port response   
       in my log files?                                                              
       This is the kernel telling you that some activity is provoking it to send     
       more ICMP or TCP reset (RST) responses than it thinks it should. ICMP         
       responses are often generated as a result of attempted connections to unused  
       UDP ports. TCP resets are generated as a result of attempted connections to   
       unopened TCP ports. Among others, these are the kinds of activities which may 
       cause these messages:                                                         
                                                                                     
         * Brute-force denial of service (DoS) attacks (as opposed to single-packet  
           attacks which exploit a specific vulnerability).                          
                                                                                     
         * Port scans which attempt to connect to a large number of ports (as        
           opposed to only trying a few well-known ports).                           
                                                                                     
       The first number in the message tells you how many packets the kernel would   
       have sent if the limit was not in place, and the second number tells you the  
       limit. You can control the limit using the net.inet.icmp.icmplim sysctl       
       variable like this, where 300 is the limit in packets per second:             
                                                                                     
       # sysctl net.inet.icmp.icmplim=300                                            
                                                                                     
       If you do not want to see messages about this in your log files, but you      
       still want the kernel to do response limiting, you can use the                
       net.inet.icmp.icmplim_output sysctl variable to disable the output like this: 
                                                                                     
       # sysctl net.inet.icmp.icmplim_output=0                                       
                                                                                     
       Finally, if you want to disable response limiting, you can set the            
       net.inet.icmp.icmplim sysctl variable (see above for an example) to 0.        
       Disabling response limiting is discouraged for the reasons listed above.      
11.18. What are these arp: unknown hardware address format error messages?           
       This means that some device on your local Ethernet is using a MAC address in  
       a format that FreeBSD does not recognize. This is probably caused by someone  
       experimenting with an Ethernet card somewhere else on the network. You will   
       see this most commonly on cable modem networks. It is harmless, and should    
       not affect the performance of your FreeBSD machine.                           
11.19. Why do I keep seeing messages like: 192.168.0.10 is on fxp1 but got reply     
       from 00:15:17:67:cf:82 on rl0, and how do I disable it?                       
       Because a packet is coming from outside the network unexpectedly. To disable  
       them, set net.link.ether.inet.log_arp_wrong_iface to 0.                       

                              Chapter 12. Security

   12.1. What is a sandbox?

   12.2. What is securelevel?

   12.3. BIND (named) is listening on some high-numbered ports. What is going
   on?

   12.4. The sendmail daemon is listening on port 587 as well as the standard
   port 25! What is going on?

   12.5. What is this UID 0 toor account? Have I been compromised?

   12.1. What is a sandbox?                                                   
         "Sandbox" is a security term. It can mean two things:                
                                                                              
           * A process which is placed inside a set of virtual walls that are 
             designed to prevent someone who breaks into the process from     
             being able to break into the wider system.                       
                                                                              
             The process is said to be able to "play" inside the walls. That  
             is, nothing the process does in regards to executing code is     
             supposed to be able to breech the walls so you do not have to do 
             a detailed audit of its code to be able to say certain things    
             about its security.                                              
                                                                              
             The walls might be a user ID, for example. This is the           
             definition used in the security(7) and named(8) man pages.       
                                                                              
             Take the ntalk service, for example (see inetd(8)). This service 
             used to run as user ID root. Now it runs as user ID tty. The tty 
             user is a sandbox designed to make it more difficult for someone 
             who has successfully hacked into the system via ntalk from being 
             able to hack beyond that user ID.                                
                                                                              
           * A process which is placed inside a simulation of the machine. It 
             means that someone who is able to break into the process may     
             believe that he can break into the wider machine but is, in      
             fact, only breaking into a simulation of that machine and not    
             modifying any real data.                                         
                                                                              
             The most common way to accomplish this is to build a simulated   
             environment in a subdirectory and then run the processes in that 
             directory chrooted (i.e., / for that process is this directory,  
             not the real / of the system).                                   
                                                                              
             Another common use is to mount an underlying file system         
             read-only and then create a file system layer on top of it that  
             gives a process a seemingly writeable view into that file        
             system. The process may believe it is able to write to those     
             files, but only the process sees the effects - other processes   
             in the system do not, necessarily.                               
                                                                              
             An attempt is made to make this sort of sandbox so transparent   
             that the user (or hacker) does not realize that he is sitting in 
             it.                                                              
                                                                              
         UNIX(R) implements two core sandboxes. One is at the process level,  
         and one is at the userid level.                                      
                                                                              
         Every UNIX(R) process is completely firewalled off from every other  
         UNIX(R) process. One process cannot modify the address space of      
         another.                                                             
                                                                              
         A UNIX(R) process is owned by a particular userid. If the user ID is 
         not the root user, it serves to firewall the process off from        
         processes owned by other users. The user ID is also used to firewall 
         off on-disk data.                                                    
   12.2. What is securelevel?                                                 
         securelevel is a security mechanism implemented in the kernel. When  
         the securelevel is positive, the kernel restricts certain tasks; not 
         even the superuser (i.e., root) is allowed to do them. The           
         securelevel mechanism limits the ability to:                         
                                                                              
           * Unset certain file flags, such as schg (the system immutable     
             flag).                                                           
                                                                              
           * Write to kernel memory via /dev/mem and /dev/kmem.               
                                                                              
           * Load kernel modules.                                             
                                                                              
           * Alter firewall rules.                                            
                                                                              
         To check the status of the securelevel on a running system, simply   
         execute the following command:                                       
                                                                              
         # sysctl -n kern.securelevel                                         
                                                                              
         The output contains the current value of the securelevel. If it is   
         positive (i.e., greater than 0), at least some of the securelevel's  
         protections are enabled.                                             
                                                                              
         The securelevel of a running system can not be lowered as this would 
         defeat its purpose. If you need to do a task that requires that the  
         securelevel be non-positive (e.g., an installworld or changing the   
         date), you will have to change the securelevel setting in            
         /etc/rc.conf (you want to look for the kern_securelevel and          
         kern_securelevel_enable variables) and reboot.                       
                                                                              
         For more information on securelevel and the specific things all the  
         levels do, please consult the init(8) manual page.                   
                                                                              
           Warning:                                                           
                                                                              
         Securelevel is not a silver bullet; it has many known deficiencies.  
         More often than not, it provides a false sense of security.          
                                                                              
         One of its biggest problems is that in order for it to be at all     
         effective, all files used in the boot process up until the           
         securelevel is set must be protected. If an attacker can get the     
         system to execute their code prior to the securelevel being set      
         (which happens quite late in the boot process since some things the  
         system must do at start-up cannot be done at an elevated             
         securelevel), its protections are invalidated. While this task of    
         protecting all files used in the boot process is not technically     
         impossible, if it is achieved, system maintenance will become a      
         nightmare since one would have to take the system down, at least to  
         single-user mode, to modify a configuration file.                    
                                                                              
         This point and others are often discussed on the mailing lists,      
         particularly the FreeBSD security mailing list. Please search the    
         archives here for an extensive discussion. A more fine-grained       
         mechanism is preferred.                                              
   12.3. BIND (named) is listening on some high-numbered ports. What is going 
         on?                                                                  
         BIND uses a random high-numbered port for outgoing queries. Recent   
         versions of it choose a new, random UDP port for each query. This    
         may cause problems for some network configurations, especially if a  
         firewall blocks incoming UDP packets on particular ports. If you     
         want to get past that firewall, you can try the avoid-v4-udp-ports   
         and avoid-v6-udp-ports options to avoid selecting random port        
         numbers within a blocked range.                                      
                                                                              
           Warning:                                                           
                                                                              
         If a port number (like 53) is specified via the query-source or      
         query-source-v6 options in /etc/namedb/named.conf, randomized port   
         selection will not be used. It is strongly recommended that these    
         options not be used to specify fixed port numbers.                   
                                                                              
         Congratulations, by the way. It is good practice to read your        
         sockstat(1) output and notice odd things!                            
   12.4. The sendmail daemon is listening on port 587 as well as the standard 
         port 25! What is going on?                                           
         Recent versions of sendmail support a mail submission feature that   
         runs over port 587. This is not yet widely supported, but is growing 
         in popularity.                                                       
   12.5. What is this UID 0 toor account? Have I been compromised?            
         Do not worry. toor is an "alternative" superuser account (toor is    
         root spelt backwards). Previously it was created when the bash(1)    
         shell was installed but now it is created by default. It is intended 
         to be used with a non-standard shell so you do not have to change    
         root's default shell. This is important as shells which are not part 
         of the base distribution (for example a shell installed from ports   
         or packages) are likely to be installed in /usr/local/bin which, by  
         default, resides on a different file system. If root's shell is      
         located in /usr/local/bin and /usr (or whatever file system contains 
         /usr/local/bin) is not mounted for some reason, root will not be     
         able to log in to fix a problem (although if you reboot into single  
         user mode you will be prompted for the path to a shell).             
                                                                              
         Some people use toor for day-to-day root tasks with a non-standard   
         shell, leaving root, with a standard shell, for single user mode or  
         emergencies. By default you cannot log in using toor as it does not  
         have a password, so log in as root and set a password for toor if    
         you want to use it.                                                  

                                Chapter 13. PPP

   13.1. I cannot make ppp(8) work. What am I doing wrong?

   13.2. Why does ppp(8) hang when I run it?

   13.3. Why will ppp(8) not dial in -auto mode?

   13.4. What does No route to host mean?

   13.5. Why does my connection drop after about 3 minutes?

   13.6. Why does my connection drop under heavy load?

   13.7. Why does my connection drop after a random amount of time?

   13.8. Why does my connection hang after a random amount of time?

   13.9. The remote end is not responding. What can I do?

   13.10. ppp(8) has hung. What can I do?

   13.11. I keep seeing errors about magic being the same. What does it mean?

   13.12. LCP negotiations continue until the connection is closed. What is
   wrong?

   13.13. Why does ppp(8) lock up when I shell out to test it?

   13.14. Why does ppp(8) over a null-modem cable never exit?

   13.15. Why does ppp(8) dial for no reason in -auto mode?

   13.16. What do these CCP errors mean?

   13.17. Why does ppp(8) not log my connection speed?

   13.18. Why does ppp(8) ignore the \ character in my chat script?

   13.19. Why does ppp(8) get a Segmentation fault, but I see no ppp.core

   13.20. Why does the process that forces a dial in -auto mode never
   connect?

   13.21. Why do most games not work with the -nat switch?

   13.22. What are FCS errors?

   13.23. None of this helps - I am desperate! What can I do?

13.1.  I cannot make ppp(8) work. What am I doing wrong?                             
       You should first read the ppp(8) manual page and the PPP section of the       
       handbook. Enable logging with the following command:                          
                                                                                     
       set log Phase Chat Connect Carrier lcp ipcp ccp command                       
                                                                                     
       This command may be typed at the ppp(8) command prompt or it may be entered   
       in the /etc/ppp/ppp.conf configuration file (the start of the default section 
       is the best place to put it). Make sure that /etc/syslog.conf (see            
       syslog.conf(5)) contains the lines below and the file /var/log/ppp.log        
       exists:                                                                       
                                                                                     
       !ppp                                                                          
       *.*        /var/log/ppp.log                                                   
                                                                                     
       You can now find out a lot about what is going on from the log file. Do not   
       worry if it does not all make sense. If you need to get help from someone, it 
       may make sense to them.                                                       
13.2.  Why does ppp(8) hang when I run it?                                           
       This is usually because your hostname will not resolve. The best way to fix   
       this is to make sure that /etc/hosts is consulted by your resolver first by   
       editing /etc/host.conf and putting the hosts line first. Then, simply put an  
       entry in /etc/hosts for your local machine. If you have no local network,     
       change your localhost line:                                                   
                                                                                     
       127.0.0.1        foo.example.com foo localhost                                
                                                                                     
       Otherwise, simply add another entry for your host. Consult the relevant       
       manual pages for more details.                                                
                                                                                     
       You should be able to successfully ping -c1 `hostname` when you are done.     
13.3.  Why will ppp(8) not dial in -auto mode?                                       
       First, check that you have got a default route. By running netstat -rn (see   
       netstat(1)), you should see two entries like this:                            
                                                                                     
       Destination        Gateway            Flags     Refs     Use     Netif Expire 
       default            10.0.0.2           UGSc        0        0      tun0        
       10.0.0.2           10.0.0.1           UH          0        0      tun0        
                                                                                     
       This is assuming that you have used the addresses from the handbook, the      
       manual page, or from ppp.conf.sample. If you do not have a default route, it  
       may be because you forgot to add the HISADDR line to ppp.conf.                
                                                                                     
       Another reason for the default route line being missing is that you have      
       mistakenly set up a default router in your /etc/rc.conf (see rc.conf(5)) file 
       and you have omitted the line below from ppp.conf:                            
                                                                                     
       delete ALL                                                                    
                                                                                     
       If this is the case, go back to the Final System Configuration section of the 
       handbook.                                                                     
13.4.  What does No route to host mean?                                              
       This error is usually due that the following section is missing in your       
       /etc/ppp/ppp.linkup:                                                          
                                                                                     
       MYADDR:                                                                       
         delete ALL                                                                  
         add 0 0 HISADDR                                                             
                                                                                     
       This is only necessary if you have a dynamic IP address or do not know the    
       address of your gateway. If you are using interactive mode, you can type the  
       following after entering packet mode (packet mode is indicated by the         
       capitalized PPP in the prompt):                                               
                                                                                     
       delete ALL                                                                    
       add 0 0 HISADDR                                                               
                                                                                     
       Refer to the PPP and Dynamic IP addresses section of the handbook for further 
       details.                                                                      
13.5.  Why does my connection drop after about 3 minutes?                            
       The default PPP timeout is 3 minutes. This can be adjusted with the following 
       line:                                                                         
                                                                                     
       set timeout NNN                                                               
                                                                                     
       where NNN is the number of seconds of inactivity before the connection is     
       closed. If NNN is zero, the connection is never closed due to a timeout. It   
       is possible to put this command in ppp.conf, or to type it at the prompt in   
       interactive mode. It is also possible to adjust it on the fly while the line  
       is active by connecting to ppp's server socket using telnet(1) or pppctl(8).  
       Refer to the ppp(8) man page for further details.                             
13.6.  Why does my connection drop under heavy load?                                 
       If you have Link Quality Reporting (LQR) configured, it is possible that too  
       many LQR packets are lost between your machine and the peer. ppp(8) deduces   
       that the line must therefore be bad, and disconnects. LQR is disabled by      
       default and can be enabled with the following line:                           
                                                                                     
       enable lqr                                                                    
13.7.  Why does my connection drop after a random amount of time?                    
       Sometimes, on a noisy phone line or even on a line with call waiting enabled, 
       your modem may hang up because it thinks (incorrectly) that it lost carrier.  
                                                                                     
       There is a setting on most modems for determining how tolerant it should be   
       to temporary losses of carrier. Refer to the modem manual for details.        
13.8.  Why does my connection hang after a random amount of time?                    
       Many people experience hung connections with no apparent explanation. The     
       first thing to establish is which side of the link is hung.                   
                                                                                     
       If you are using an external modem, you can simply try using ping(8) to see   
       if the TD light is flashing when you transmit data. If it flashes (and the RD 
       light does not), the problem is with the remote end. If TD does not flash,    
       the problem is local. With an internal modem, you will need to use the set    
       server command in ppp.conf. When the hang occurs, connect to ppp(8) using     
       pppctl(8). If your network connection suddenly revives (PPP was revived due   
       to the activity on the diagnostic socket) or if you cannot connect (assuming  
       the set socket command succeeded at startup time), the problem is local. If   
       you can connect and things are still hung, enable local async logging with    
       set log local async and use ping(8) from another window or terminal to make   
       use of the link. The async logging will show you the data being transmitted   
       and received on the link. If data is going out and not coming back, the       
       problem is remote.                                                            
                                                                                     
       Having established whether the problem is local or remote, you now have two   
       possibilities:                                                                
                                                                                     
         * If the problem is remote, read on entry Q: 13.9.                          
                                                                                     
         * If the problem is local, read on entry Q: 13.10.                          
13.9.  The remote end is not responding. What can I do?                              
       There is very little you can do about this. Most ISPs will refuse to help if  
       you are not running a Microsoft(R) OS. You can enable lqr in your ppp.conf,   
       allowing ppp(8) to detect the remote failure and hang up, but this detection  
       is relatively slow and therefore not that useful. You may want to avoid       
       telling your ISP that you are running user-PPP.                               
                                                                                     
       First, try disabling all local compression by adding the following to your    
       configuration:                                                                
                                                                                     
       disable pred1 deflate deflate24 protocomp acfcomp shortseq vj                 
       deny pred1 deflate deflate24 protocomp acfcomp shortseq vj                    
                                                                                     
       Then reconnect to ensure that this makes no difference. If things improve or  
       if the problem is solved completely, determine which setting makes the        
       difference through trial and error. This will provide good ammunition when    
       you contact your ISP (although it may make it apparent that you are not       
       running a Microsoft(R) product).                                              
                                                                                     
       Before contacting your ISP, enable async logging locally and wait until the   
       connection hangs again. This may use up quite a bit of disk space. The last   
       data read from the port may be of interest. It is usually ASCII data, and may 
       even describe the problem (Memory fault, Core dumped).                        
                                                                                     
       If your ISP is helpful, they should be able to enable logging on their end,   
       then when the next link drop occurs, they may be able to tell you why their   
       side is having a problem.                                                     
13.10. ppp(8) has hung. What can I do?                                               
       Your best bet here is to rebuild ppp(8) with debugging information, and then  
       use gdb(1) to grab a stack trace from the ppp process that is stuck. To       
       rebuild the ppp utility with debugging information, you can type:             
                                                                                     
       # cd /usr/src/usr.sbin/ppp                                                    
       # env DEBUG_FLAGS='-g' make clean                                             
       # env DEBUG_FLAGS='-g' make install                                           
                                                                                     
       Then you should restart ppp and wait until it hangs again. When the debug     
       build of ppp hangs, start gdb on the stuck process by typing:                 
                                                                                     
       # gdb ppp `pgrep ppp`                                                         
                                                                                     
       At the gdb prompt, you can use the bt or where commands to get a stack trace. 
       Save the output of your gdb session, and "detach" from the running process by 
       typing quit.                                                                  
13.11. I keep seeing errors about magic being the same. What does it mean?           
       Occasionally, just after connecting, you may see messages in the log that say 
       Magic is same. Sometimes, these messages are harmless, and sometimes one side 
       or the other exits. Most PPP implementations cannot survive this problem, and 
       even if the link seems to come up, you will see repeated configure requests   
       and configure acknowledgments in the log file until ppp(8) eventually gives   
       up and closes the connection.                                                 
                                                                                     
       This normally happens on server machines with slow disks that are spawning a  
       getty(8) on the port, and executing ppp(8) from a login script or program     
       after login. There were reports of it happening consistently when using       
       slirp. The reason is that in the time taken between getty(8) exiting and      
       ppp(8) starting, the client-side ppp(8) starts sending Line Control Protocol  
       (LCP) packets. Because ECHO is still switched on for the port on the server,  
       the client ppp(8) sees these packets "reflect" back.                          
                                                                                     
       One part of the LCP negotiation is to establish a magic number for each side  
       of the link so that "reflections" can be detected. The protocol says that     
       when the peer tries to negotiate the same magic number, a NAK should be sent  
       and a new magic number should be chosen. During the period that the server    
       port has ECHO turned on, the client ppp(8) sends LCP packets, sees the same   
       magic in the reflected packet and NAKs it. It also sees the NAK reflect       
       (which also means ppp(8) must change its magic). This produces a potentially  
       enormous number of magic number changes, all of which are happily piling into 
       the server's tty buffer. As soon as ppp(8) starts on the server, it is        
       flooded with magic number changes and almost immediately decides it has tried 
       enough to negotiate LCP and gives up. Meanwhile, the client, who no longer    
       sees the reflections, becomes happy just in time to see a hangup from the     
       server.                                                                       
                                                                                     
       This can be avoided by allowing the peer to start negotiating with the        
       following line in ppp.conf:                                                   
                                                                                     
       set openmode passive                                                          
                                                                                     
       This tells ppp(8) to wait for the server to initiate LCP negotiations. Some   
       servers however may never initiate negotiations. If this is the case, you can 
       do something like:                                                            
                                                                                     
       set openmode active 3                                                         
                                                                                     
       This tells ppp(8) to be passive for 3 seconds, and then to start sending LCP  
       requests. If the peer starts sending requests during this period, ppp(8) will 
       immediately respond rather than waiting for the full 3 second period.         
13.12. LCP negotiations continue until the connection is closed. What is wrong?      
       There is currently an implementation mis-feature in ppp(8) where it does not  
       associate LCP, CCP & IPCP responses with their original requests. As a        
       result, if one PPP implementation is more than 6 seconds slower than the      
       other side, the other side will send two additional LCP configuration         
       requests. This is fatal.                                                      
                                                                                     
       Consider two implementations, A and B. A starts sending LCP requests          
       immediately after connecting and B takes 7 seconds to start. When B starts, A 
       has sent 3 LCP REQs. We are assuming the line has ECHO switched off,          
       otherwise we would see magic number problems as described in the previous     
       section. B sends a REQ, then an ACK to the first of A's REQs. This results in 
       A entering the OPENED state and sending and ACK (the first) back to B. In the 
       meantime, B sends back two more ACKs in response to the two additional REQs   
       sent by A before B started up. B then receives the first ACK from A and       
       enters the OPENED state. A receives the second ACK from B and goes back to    
       the REQ-SENT state, sending another (forth) REQ as per the RFC. It then       
       receives the third ACK and enters the OPENED state. In the meantime, B        
       receives the forth REQ from A, resulting in it reverting to the ACK-SENT      
       state and sending another (second) REQ and (forth) ACK as per the RFC. A gets 
       the REQ, goes into REQ-SENT and sends another REQ. It immediately receives    
       the following ACK and enters OPENED.                                          
                                                                                     
       This goes on until one side figures out that they are getting nowhere and     
       gives up.                                                                     
                                                                                     
       The best way to avoid this is to configure one side to be passive - that is,  
       make one side wait for the other to start negotiating. This can be done with  
       the following command:                                                        
                                                                                     
       set openmode passive                                                          
                                                                                     
       Care should be taken with this option. You should also use this command to    
       limit the amount of time that ppp(8) waits for the peer to begin              
       negotiations:                                                                 
                                                                                     
       set stopped N                                                                 
                                                                                     
       Alternatively, the following command (where N is the number of seconds to     
       wait before starting negotiations) can be used:                               
                                                                                     
       set openmode active N                                                         
                                                                                     
       Check the manual page for details.                                            
13.13. Why does ppp(8) lock up when I shell out to test it?                          
       When you execute the shell or ! command, ppp(8) executes a shell (or if you   
       have passed any arguments, ppp(8) will execute those arguments). The ppp      
       program will wait for the command to complete before continuing. If you       
       attempt to use the PPP link while running the command, the link will appear   
       to have frozen. This is because ppp(8) is waiting for the command to          
       complete.                                                                     
                                                                                     
       To execute commands like this, use !bg instead. This will execute the given   
       command in the background, and ppp(8) can continue to service the link.       
13.14. Why does ppp(8) over a null-modem cable never exit?                           
       There is no way for ppp(8) to automatically determine that a direct           
       connection has been dropped. This is due to the lines that are used in a      
       null-modem serial cable. When using this sort of connection, LQR should       
       always be enabled with the following line:                                    
                                                                                     
       enable lqr                                                                    
                                                                                     
       LQR is accepted by default if negotiated by the peer.                         
13.15. Why does ppp(8) dial for no reason in -auto mode?                             
       If ppp(8) is dialing unexpectedly, you must determine the cause, and set up   
       Dial filters (dfilters) to prevent such dialing.                              
                                                                                     
       To determine the cause, use the following line:                               
                                                                                     
       set log +tcp/ip                                                               
                                                                                     
       This will log all traffic through the connection. The next time the line      
       comes up unexpectedly, you will see the reason logged with a convenient       
       timestamp next to it.                                                         
                                                                                     
       You can now disable dialing under these circumstances. Usually, this sort of  
       problem arises due to DNS lookups. To prevent DNS lookups from establishing a 
       connection (this will not prevent ppp(8) from passing the packets through an  
       established connection), use the following:                                   
                                                                                     
       set dfilter 1 deny udp src eq 53                                              
       set dfilter 2 deny udp dst eq 53                                              
       set dfilter 3 permit 0/0 0/0                                                  
                                                                                     
       This is not always suitable, as it will effectively break your demand-dial    
       capabilities - most programs will need a DNS lookup before doing any other    
       network related things.                                                       
                                                                                     
       In the DNS case, you should try to determine what is actually trying to       
       resolve a host name. A lot of the time, sendmail(8) is the culprit. You       
       should make sure that you tell sendmail not to do any DNS lookups in its      
       configuration file. See the section on using email with a dialup connection   
       in the FreeBSD Handbook for details on how to create your own configuration   
       file and what should go into it. You may also want to add the following line  
       to .mc:                                                                       
                                                                                     
       define(`confDELIVERY_MODE', `d')dnl                                           
                                                                                     
       This will make sendmail queue everything until the queue is run (usually,     
       sendmail is run with -bd -q30m, telling it to run the queue every 30 minutes) 
       or until a sendmail -q is done (perhaps from your ppp.linkup).                
13.16. What do these CCP errors mean?                                                
       I keep seeing the following errors in my log file:                            
                                                                                     
       CCP: CcpSendConfigReq                                                         
       CCP: Received Terminate Ack (1) state = Req-Sent (6)                          
                                                                                     
       This is because ppp(8) is trying to negotiate Predictor1 compression, and the 
       peer does not want to negotiate any compression at all. The messages are      
       harmless, but if you wish to remove them, you can disable Predictor1          
       compression locally too:                                                      
                                                                                     
       disable pred1                                                                 
13.17. Why does ppp(8) not log my connection speed?                                  
       To log all lines of your modem "conversation", you must enable the following: 
                                                                                     
       set log +connect                                                              
                                                                                     
       This will make ppp(8) log everything up until the last requested "expect"     
       string.                                                                       
                                                                                     
       If you wish to see your connect speed and are using PAP or CHAP (and          
       therefore do not have anything to "chat" after the CONNECT in the dial script 
       - no set login script), you must make sure that you instruct ppp(8) to        
       "expect" the whole CONNECT line, something like this:                         
                                                                                     
       set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 4 \                           
         \"\" ATZ OK-ATZ-OK ATDT\\T TIMEOUT 60 CONNECT \\c \\n"                      
                                                                                     
       Here, we get our CONNECT, send nothing, then expect a line-feed, forcing      
       ppp(8) to read the whole CONNECT response.                                    
13.18. Why does ppp(8) ignore the \ character in my chat script?                     
       The ppp utility parses each line in your config files so that it can          
       interpret strings such as set phone "123 456 789" correctly and realize that  
       the number is actually only one argument. To specify a " character, you must  
       escape it using a backslash (\).                                              
                                                                                     
       When the chat interpreter parses each argument, it re-interprets the argument 
       to find any special escape sequences such as \P or \T (see the manual page).  
       As a result of this double-parsing, you must remember to use the correct      
       number of escapes.                                                            
                                                                                     
       If you wish to actually send a \ character to (say) your modem, you would     
       need something like:                                                          
                                                                                     
       set dial "\"\" ATZ OK-ATZ-OK AT\\\\X OK"                                      
                                                                                     
       It will result in the following sequence:                                     
                                                                                     
       ATZ                                                                           
       OK                                                                            
       AT\X                                                                          
       OK                                                                            
                                                                                     
       Or:                                                                           
                                                                                     
       set phone 1234567                                                             
       set dial "\"\" ATZ OK ATDT\\T"                                                
                                                                                     
       It will result in the following sequence:                                     
                                                                                     
       ATZ                                                                           
       OK                                                                            
       ATDT1234567                                                                   
13.19. Why does ppp(8) get a Segmentation fault, but I see no ppp.core               
       The ppp utility (or any other program for that matter) should never dump      
       core. Because ppp(8) runs setuid (with an effective user ID of 0), the        
       operating system will not write core image of ppp(8) to disk before           
       terminating it. If, however ppp(8) is actually terminating due to a           
       segmentation violation or some other signal that normally causes core to be   
       dumped, and you are sure you are using the latest version (see the start of   
       this section), then you should install the system sources and do the          
       following:                                                                    
                                                                                     
       # cd /usr/src/usr.sbin/ppp                                                    
       # echo STRIP= >> /etc/make.conf                                               
       # echo CFLAGS+=-g >> /etc/make.conf                                           
       # make install clean                                                          
                                                                                     
       You will now have a debuggable version of ppp(8) installed. You will have to  
       be root to run ppp(8) as all of its privileges have been revoked. When you    
       start ppp(8), take a careful note of what your current directory was at the   
       time.                                                                         
                                                                                     
       Now, if and when ppp(8) receives the segmentation violation, it will dump a   
       core file called ppp.core. You should then do the following:                  
                                                                                     
       % su                                                                          
       # gdb /usr/sbin/ppp ppp.core                                                  
       (gdb) bt                                                                      
       .....                                                                         
       (gdb) f 0                                                                     
       ....                                                                          
       (gdb) i args                                                                  
       ....                                                                          
       (gdb) l                                                                       
       .....                                                                         
                                                                                     
       All of this information should be given alongside your question, making it    
       possible to diagnose the problem.                                             
                                                                                     
       If you are familiar with gdb(1), you may wish to find out some other bits and 
       pieces such as what actually caused the dump or the addresses and values of   
       the relevant variables.                                                       
13.20. Why does the process that forces a dial in -auto mode never connect?          
       This was a known problem with ppp(8) set up to negotiate a dynamic local IP   
       number with the peer in -auto mode. It has been fixed a long time ago -       
       search the manual page for iface.                                             
                                                                                     
       The problem was that when that initial program calls connect(2), the IP       
       number of the tun(4) interface is assigned to the socket endpoint. The kernel 
       creates the first outgoing packet and writes it to the tun(4) device. ppp(8)  
       then reads the packet and establishes a connection. If, as a result of        
       ppp(8)'s dynamic IP assignment, the interface address is changed, the         
       original socket endpoint will be invalid. Any subsequent packets sent to the  
       peer will usually be dropped. Even if they are not, any responses will not    
       route back to the originating machine as the IP number is no longer owned by  
       that machine.                                                                 
                                                                                     
       There are several theoretical ways to approach this problem. It would be      
       nicest if the peer would re-assign the same IP number if possible. The        
       current version of ppp(8) does this, but most other implementations do not.   
                                                                                     
       The easiest method from our side would be to never change the tun(4)          
       interface IP number, but instead to change all outgoing packets so that the   
       source IP number is changed from the interface IP to the negotiated IP on the 
       fly. This is essentially what the iface-alias option in the latest version of 
       ppp(8) is doing (with the help of libalias(3) and ppp(8)'s -nat switch) - it  
       is maintaining all previous interface addresses and NATing them to the last   
       negotiated address.                                                           
                                                                                     
       Another alternative (and probably the most reliable) would be to implement a  
       system call that changes all bound sockets from one IP to another. ppp(8)     
       would use this call to modify the sockets of all existing programs when a new 
       IP number is negotiated. The same system call could be used by DHCP clients   
       when they are forced to call the bind() function for their sockets.           
                                                                                     
       Yet another possibility is to allow an interface to be brought up without an  
       IP number. Outgoing packets would be given an IP number of 255.255.255.255 up 
       until the first SIOCAIFADDR ioctl(2) is done. This would result in fully      
       binding the socket. It would be up to ppp(8) to change the source IP number,  
       but only if it is set to 255.255.255.255, and only the IP number and IP       
       checksum would need to change. This, however is a bit of a hack as the kernel 
       would be sending bad packets to an improperly configured interface, on the    
       assumption that some other mechanism is capable of fixing things              
       retrospectively.                                                              
13.21. Why do most games not work with the -nat switch?                              
       The reason games and the like do not work when libalias(3) is in use is that  
       the machine on the outside will try to open a connection or send              
       (unsolicited) UDP packets to the machine on the inside. The NAT software does 
       not know that it should send these packets to the interior machine.           
                                                                                     
       To make things work, make sure that the only thing running is the software    
       that you are having problems with, then either run tcpdump(1) on the tun(4)   
       interface of the gateway or enable ppp(8) TCP/IP logging (set log +tcp/ip) on 
       the gateway.                                                                  
                                                                                     
       When you start the offending software, you should see packets passing through 
       the gateway machine. When something comes back from the outside, it will be   
       dropped (that is the problem). Note the port number of these packets then     
       shut down the offending software. Do this a few times to see if the port      
       numbers are consistent. If they are, then the following line in the relevant  
       section of /etc/ppp/ppp.conf will make the software functional:               
                                                                                     
       nat port proto internalmachine:port port                                      
                                                                                     
       where proto is either tcp or udp, internalmachine is the machine that you     
       want the packets to be sent to and port is the destination port number of the 
       packets.                                                                      
                                                                                     
       You will not be able to use the software on other machines without changing   
       the above command, and running the software on two internal machines at the   
       same time is out of the question - after all, the outside world is seeing     
       your entire internal network as being just a single machine.                  
                                                                                     
       If the port numbers are not consistent, there are three more options:         
                                                                                     
        1. Submit support in libalias(3). Examples of "special cases" can be found   
           in /usr/src/sys/netinet/libalias/alias_*.c (alias_ftp.c is a good         
           prototype). This usually involves reading certain recognized outgoing     
           packets, identifying the instruction that tells the outside machine to    
           initiate a connection back to the internal machine on a specific (random) 
           port and setting up a "route" in the alias table so that the subsequent   
           packets know where to go.                                                 
                                                                                     
           This is the most difficult solution, but it is the best and will make the 
           software work with multiple machines.                                     
                                                                                     
        2. Use a proxy. The application may support socks5 for example, or may have  
           a "passive" option that avoids ever requesting that the peer open         
           connections back to the local machine.                                    
                                                                                     
        3. Redirect everything to the internal machine using nat addr. This is the   
           sledge-hammer approach.                                                   
13.22. What are FCS errors?                                                          
       FCS stands for Frame Check Sequence. Each PPP packet has a checksum attached  
       to ensure that the data being received is the data being sent. If the FCS of  
       an incoming packet is incorrect, the packet is dropped and the HDLC FCS count 
       is increased. The HDLC error values can be displayed using the show hdlc      
       command.                                                                      
                                                                                     
       If your link is bad (or if your serial driver is dropping packets), you will  
       see the occasional FCS error. This is not usually worth worrying about        
       although it does slow down the compression protocols substantially. If you    
       have an external modem, make sure your cable is properly shielded from        
       interference - this may eradicate the problem.                                
                                                                                     
       If your link freezes as soon as you have connected and you see a large number 
       of FCS errors, this may be because your link is not 8-bit clean. Make sure    
       your modem is not using software flow control (XON/XOFF). If your datalink    
       must use software flow control, use the command set accmap 0x000a0000 to tell 
       ppp(8) to escape the ^Q and ^S characters.                                    
                                                                                     
       Another reason for seeing too many FCS errors may be that the remote end has  
       stopped talking PPP. You may want to enable async logging at this point to    
       determine if the incoming data is actually a login or shell prompt. If you    
       have a shell prompt at the remote end, it is possible to terminate ppp(8)     
       without dropping the line by using close lcp (a following term) will          
       reconnect you to the shell on the remote machine.                             
                                                                                     
       If nothing in your log file indicates why the link might have been            
       terminated, you should ask the remote administrator (your ISP?) why the       
       session was terminated.                                                       
13.23. None of this helps - I am desperate! What can I do?                           
       If all else fails, send as much information as you can, including your config 
       files, how you are starting ppp(8), the relevant parts of your log file and   
       the output of netstat -rn (before and after connecting) to the FreeBSD        
       general questions mailing list and someone should point you in the right      
       direction.                                                                    

                       Chapter 14. Serial Communications

   This section answers common questions about serial communications with
   FreeBSD. PPP is covered in the Networking section.

   14.1. Which multi-port serial cards are supported by FreeBSD?

   14.2. How do I get the boot: prompt to show on the serial console?

   14.3. How do I tell if FreeBSD found my serial ports or modem cards?

   14.4. How do I access the serial ports on FreeBSD?

   14.5. How do I enable support for a multiport serial card?

   14.6. Can I set the default serial parameters for a port?

   14.7. How can I enable dialup logins on my modem?

   14.8. How can I connect a dumb terminal to my FreeBSD box?

   14.9. Why can I not run tip or cu?

14.1. Which multi-port serial cards are supported by FreeBSD?                       
      There is a list of these in the Serial Communications chapter of the          
      handbook.                                                                     
                                                                                    
      Most multi-port PCI cards that are based on 16550 or clones are supported     
      with no extra effort.                                                         
                                                                                    
      Some unnamed clone cards have also been known to work, especially those that  
      claim to be AST compatible.                                                   
                                                                                    
      Check uart(4) and sio(4) to get more information on configuring such cards.   
14.2. How do I get the boot: prompt to show on the serial console?                  
      See this section of the handbook.                                             
14.3. How do I tell if FreeBSD found my serial ports or modem cards?                
      As the FreeBSD kernel boots, it will probe for the serial ports in your       
      system for which the kernel was configured. You can either watch your system  
      closely for the messages it prints or run this command after your system is   
      up and running:                                                               
                                                                                    
      % dmesg | grep -E "^sio[0-9]"                                                 
                                                                                    
      Here is some example output from the above command:                           
                                                                                    
      sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0 
      sio0: type 16550A                                                             
      sio1: <16550A-compatible COM port> port 0x2f8-0x2ff irq 3 on acpi0            
      sio1: type 16550A                                                             
                                                                                    
      This shows two serial ports. The first is on IRQ 4, is using port address     
      0x3f8, and has a 16550A-type UART chip. The second uses the same kind of chip 
      but is on IRQ 3 and is at port address 0x2f8. Internal modem cards are        
      treated just like serial ports - except that they always have a modem         
      "attached" to the port.                                                       
                                                                                    
      The GENERIC kernel includes support for two serial ports using the same IRQ   
      and port address settings in the above example. If these settings are not     
      right for your system, or if you have added modem cards or have more serial   
      ports than your kernel is configured for, just reconfigure your kernel. See   
      section about building a kernel for more details.                             
14.4. How do I access the serial ports on FreeBSD?                                  
      The third serial port, sio2 (see sio(4), known as COM3 in DOS), is on         
      /dev/cuad2 for dial-out devices, and on /dev/ttyd2 for dial-in devices. What  
      is the difference between these two classes of devices?                       
                                                                                    
      You use ttydX for dial-ins. When opening /dev/ttydX in blocking mode, a       
      process will wait for the corresponding cuadX device to become inactive, and  
      then wait for the carrier detect line to go active. When you open the cuadX   
      device, it makes sure the serial port is not already in use by the ttydX      
      device. If the port is available, it "steals" it from the ttydX device. Also, 
      the cuadX device does not care about carrier detect. With this scheme and an  
      auto-answer modem, you can have remote users log in and you can still dial    
      out with the same modem and the system will take care of all the conflicts.   
14.5. How do I enable support for a multiport serial card?                          
      Again, the section on kernel configuration provides information about         
      configuring your kernel. For a multiport serial card, place an sio(4) line    
      for each serial port on the card in the device.hints(5) file. But place the   
      IRQ specifiers on only one of the entries. All of the ports on the card       
      should share one IRQ. For consistency, use the last serial port to specify    
      the IRQ. Also, specify the following option in the kernel configuration file: 
                                                                                    
      options COM_MULTIPORT                                                         
                                                                                    
      The following /boot/device.hints example is for an AST 4-port serial card on  
      IRQ 12:                                                                       
                                                                                    
      hint.sio.4.at="isa"                                                           
      hint.sio.4.port="0x2a0"                                                       
      hint.sio.4.flags="0x701"                                                      
      hint.sio.5.at="isa"                                                           
      hint.sio.5.port="0x2a8"                                                       
      hint.sio.5.flags="0x701"                                                      
      hint.sio.6.at="isa"                                                           
      hint.sio.6.port="0x2b0"                                                       
      hint.sio.6.flags="0x701"                                                      
      hint.sio.7.at="isa"                                                           
      hint.sio.7.port="0x2b8"                                                       
      hint.sio.7.flags="0x701"                                                      
      hint.sio.7.irq="12"                                                           
                                                                                    
      The flags indicate that the master port has minor number 7 (0x700), and all   
      the ports share an IRQ (0x001).                                               
14.6. Can I set the default serial parameters for a port?                           
      See the Serial Communications section in the FreeBSD Handbook.                
14.7. How can I enable dialup logins on my modem?                                   
      Please read the section about Dial-in Services in the FreeBSD Handbook.       
14.8. How can I connect a dumb terminal to my FreeBSD box?                          
      You can find this information in the Terminals section of the FreeBSD         
      Handbook.                                                                     
14.9. Why can I not run tip or cu?                                                  
      On your system, the programs tip(1) and cu(1) can only access the             
      /var/spool/lock directory via user uucp and group dialer. You can use the     
      group dialer to control who has access to your modem or remote systems. Just  
      add yourself to group dialer.                                                 
                                                                                    
      Alternatively, you can let everyone on your system run tip(1) and cu(1) by    
      typing:                                                                       
                                                                                    
      # chmod 4511 /usr/bin/cu                                                      
      # chmod 4511 /usr/bin/tip                                                     

                      Chapter 15. Miscellaneous Questions

   15.1. FreeBSD uses a lot of swap space even when the computer has free
   memory left. Why?

   15.2. Why does top show very little free memory even when I have very few
   programs running?

   15.3. Why will chmod not change the permissions on symlinks?

   15.4. Can I run DOS binaries under FreeBSD?

   15.5. What do I need to do to translate a FreeBSD document into my native
   language?

   15.6. Why does my email to any address at FreeBSD.org bounce?

   15.7. Where can I find a free FreeBSD account?

   15.8. What is the cute little red guy's name?

   15.9. Can I use the BSD daemon image?

   15.10. Do you have any BSD daemon images I could use?

   15.11. I have seen an acronym or other term on the mailing lists and I do
   not understand what it means. Where should I look?

   15.12. Why should I care what color the bikeshed is?

   15.1.  FreeBSD uses a lot of swap space even when the computer has free    
          memory left. Why?                                                   
          FreeBSD will proactively move entirely idle, unused pages of main   
          memory into swap in order to make more main memory available for    
          active use. This heavy use of swap is balanced by using the extra   
          free memory for cacheing.                                           
                                                                              
          Note that while FreeBSD is proactive in this regard, it does not    
          arbitrarily decide to swap pages when the system is truly idle.     
          Thus you will not find your system all paged out when you get up in 
          the morning after leaving it idle overnight.                        
   15.2.  Why does top show very little free memory even when I have very few 
          programs running?                                                   
          The simple answer is that free memory is wasted memory. Any memory  
          that your programs do not actively allocate is used within the      
          FreeBSD kernel as disk cache. The values shown by top(1) labeled as 
          Inact, Cache, and Buf are all cached data at different aging        
          levels. This cached data means the system does not have to access a 
          slow disk again for data it has accessed recently, thus increasing  
          overall performance. In general, a low value shown for Free memory  
          in top(1) is good, provided it is not very low.                     
   15.3.  Why will chmod not change the permissions on symlinks?              
          Symlinks do not have permissions, and by default, chmod(1) will     
          follow symlinks to change the permissions on the source file, if    
          possible. So if you have a file, foo, and a symlink to that file,   
          bar, then this command will always succeed.                         
                                                                              
          % chmod g-w bar                                                     
                                                                              
          However, the permissions on bar will not have changed.              
                                                                              
          When changing modes of the file hierarchies rooted in the files     
          instead of the files themselves, you have to use either -H or -L    
          together with -R to make this work. See chmod(1) and symlink(7) for 
          more information.                                                   
                                                                              
            Warning:                                                          
                                                                              
          -R does a recursive chmod(1). Be careful about specifying           
          directories or symlinks to directories to chmod(1). If you want to  
          change the permissions of a directory referenced by a symlink, use  
          chmod(1) without any options and follow the symlink with a trailing 
          slash (/). For example, if foo is a symlink to directory bar, and   
          you want to change the permissions of foo (actually bar), you would 
          do something like:                                                  
                                                                              
          % chmod 555 foo/                                                    
                                                                              
          With the trailing slash, chmod(1) will follow the symlink, foo, to  
          change the permissions of the directory, bar.                       
   15.4.  Can I run DOS binaries under FreeBSD?                               
          Yes, you can use emulators/doscmd, a DOS emulation program,         
          available in the FreeBSD Ports Collection.                          
                                                                              
          If doscmd will not suffice, the add-on utility emulators/pcemu      
          emulates an 8088 and enough BIOS services to run many DOS text mode 
          applications. It requires the X Window System.                      
                                                                              
          You may also try emulators/dosbox from the FreeBSD Ports            
          Collection. The main focus of this application is emulating old DOS 
          games using the local file system for files.                        
   15.5.  What do I need to do to translate a FreeBSD document into my native 
          language?                                                           
          See the Translation FAQ in the FreeBSD Documentation Project        
          Primer.                                                             
   15.6.  Why does my email to any address at FreeBSD.org bounce?             
          The FreeBSD.org mail system implements some Postfix checks on       
          incoming mail and rejects mail that is either from misconfigured    
          relays or otherwise appears likely to be spam. Some of the specific 
          requirements are:                                                   
                                                                              
            * The IP address of the SMTP client must "reverse-resolve" to a   
              forward confirmed hostname.                                     
                                                                              
            * The fully-qualified hostname given in the SMTP conversation     
              (either HELO or EHLO) must resolve to the IP address of the     
              client.                                                         
                                                                              
          Other advice to help your mail reach its destination include:       
                                                                              
            * Mail should be sent in plain text, and messages sent to mailing 
              lists should generally be no more than 200KB in length.         
                                                                              
            * Avoid excessive cross posting. Choose one mailing list which    
              seems most relevant and send it there.                          
                                                                              
          If you still have trouble with email infrastructure at FreeBSD.org  
          send a note with the details to <postmaster@freebsd.org>; Include a 
          date/time interval so that logs may be reviewed - and note that we  
          only keep one week's worth of mail logs. (Be sure to specify the    
          time zone or offset from UTC.)                                      
   15.7.  Where can I find a free FreeBSD account?                            
          While FreeBSD does not provide open access to any of their servers, 
          others do provide open access UNIX(R) systems. The charge varies    
          and limited services may be available.                              
                                                                              
          Arbornet, Inc, also known as M-Net, has been providing open access  
          to UNIX(R) systems since 1983. Starting on an Altos running System  
          III, the site switched to BSD/OS in 1991. In June of 2000, the site 
          switched again to FreeBSD. M-Net can be accessed via telnet and SSH 
          and provides basic access to the entire FreeBSD software suite.     
          However, network access is limited to members and patrons who       
          donate to the system, which is run as a non-profit organization.    
          M-Net also provides an bulletin board system and interactive chat.  
   15.8.  What is the cute little red guy's name?                             
          He does not have one, and is just called "the BSD daemon". If you   
          insist upon using a name, call him "beastie". Note that "beastie"   
          is pronounced "BSD".                                                
                                                                              
          You can learn more about the BSD daemon on his home page.           
   15.9.  Can I use the BSD daemon image?                                     
          Perhaps. The BSD daemon is copyrighted by Marshall Kirk McKusick.   
          You will want to check his Statement on the Use of the BSD Daemon   
          Figure for detailed usage terms.                                    
                                                                              
          In summary, you are free to use the image in a tasteful manner, for 
          personal use, so long as appropriate credit is given. If you want   
          to use him commercially, you must contact Kirk McKusick             
          <mckusick@FreeBSD.org>. More details are available on the BSD       
          Daemon's home page.                                                 
   15.10. Do you have any BSD daemon images I could use?                      
          You will find eps and Xfig drawings under                           
          /usr/share/examples/BSD_daemon/.                                    
   15.11. I have seen an acronym or other term on the mailing lists and I do  
          not understand what it means. Where should I look?                  
          Please see the FreeBSD Glossary.                                    
   15.12. Why should I care what color the bikeshed is?                       
          The really, really short answer is that you should not. The         
          somewhat longer answer is that just because you are capable of      
          building a bikeshed does not mean you should stop others from       
          building one just because you do not like the color they plan to    
          paint it. This is a metaphor indicating that you need not argue     
          about every little feature just because you know enough to do so.   
          Some people have commented that the amount of noise generated by a  
          change is inversely proportional to the complexity of the change.   
                                                                              
          The longer and more complete answer is that after a very long       
          argument about whether sleep(1) should take fractional second       
          arguments, Poul-Henning Kamp <phk@FreeBSD.org> posted a long        
          message entitled "A bike shed (any color will do) on greener        
          grass...". The appropriate portions of that message are quoted      
          below.                                                              
                                                                              
            "What is it about this bike shed?" Some of you have asked me.     
                                                                              
            It is a long story, or rather it is an old story, but it is       
            quite short actually. C. Northcote Parkinson wrote a book in      
            the early 1960s, called "Parkinson's Law", which contains a lot   
            of insight into the dynamics of management.                       
                                                                              
            [snip a bit of commentary on the book]                            
                                                                              
            In the specific example involving the bike shed, the other        
            vital component is an atomic power-plant, I guess that            
            illustrates the age of the book.                                  
                                                                              
            Parkinson shows how you can go into the board of directors and    
            get approval for building a multi-million or even billion         
            dollar atomic power plant, but if you want to build a bike shed   
            you will be tangled up in endless discussions.                    
                                                                              
            Parkinson explains that this is because an atomic plant is so     
            vast, so expensive and so complicated that people cannot grasp    
            it, and rather than try, they fall back on the assumption that    
            somebody else checked all the details before it got this far.     
            Richard P. Feynmann gives a couple of interesting, and very       
            much to the point, examples relating to Los Alamos in his         
            books.                                                            
                                                                              
            A bike shed on the other hand. Anyone can build one of those      
            over a weekend, and still have time to watch the game on TV. So   
            no matter how well prepared, no matter how reasonable you are     
            with your proposal, somebody will seize the chance to show that   
            he is doing his job, that he is paying attention, that he is      
            here.                                                             
                                                                              
            In Denmark we call it "setting your fingerprint". It is about     
            personal pride and prestige, it is about being able to point      
            somewhere and say "There! I did that." It is a strong trait in    
            politicians, but present in most people given the chance. Just    
            think about footsteps in wet cement.                              
            --Poul-Henning Kamp <phk@FreeBSD.org> on freebsd-hackers, October 
                                                                      2, 1999 

                        Chapter 16. The FreeBSD Funnies

   16.1. How cool is FreeBSD?

   16.2. Who is scratching in my memory banks??

   16.3. How many FreeBSD hackers does it take to change a lightbulb?

   16.4. Where does data written to /dev/null go?

   16.5. My colleague sits at the computer too much, how can I prank her?

   16.1. How cool is FreeBSD?                                                 
         Q. Has anyone done any temperature testing while running FreeBSD? I  
         know Linux(R) runs cooler than DOS, but have never seen a mention of 
         FreeBSD. It seems to run really hot.                                 
                                                                              
         A. No, but we have done numerous taste tests on blindfolded          
         volunteers who have also had 250 micrograms of LSD-25 administered   
         beforehand. 35% of the volunteers said that FreeBSD tasted sort of   
         orange, whereas Linux(R) tasted like purple haze. Neither group      
         mentioned any significant variances in temperature. We eventually    
         had to throw the results of this survey out entirely anyway when we  
         found that too many volunteers were wandering out of the room during 
         the tests, thus skewing the results. We think most of the volunteers 
         are at Apple now, working on their new "scratch and sniff" GUI. It   
         is a funny old business we are in!                                   
                                                                              
         Seriously, FreeBSD uses the HLT (halt) instruction when the system   
         is idle thus lowering its energy consumption and therefore the heat  
         it generates. Also if you have ACPI (Advanced Configuration and      
         Power Interface) configured, then FreeBSD can also put the CPU into  
         a low power mode.                                                    
   16.2. Who is scratching in my memory banks??                               
         Q. Is there anything "odd" that FreeBSD does when compiling the      
         kernel which would cause the memory to make a scratchy sound? When   
         compiling (and for a brief moment after recognizing the floppy drive 
         upon startup, as well), a strange scratchy sound emanates from what  
         appears to be the memory banks.                                      
                                                                              
         A. Yes! You will see frequent references to "daemons" in the BSD     
         documentation, and what most people do not know is that this refers  
         to genuine, non-corporeal entities that now possess your computer.   
         The scratchy sound coming from your memory is actually high-pitched  
         whispering exchanged among the daemons as they best decide how to    
         deal with various system administration tasks.                       
                                                                              
         If the noise gets to you, a good fdisk /mbr from DOS will get rid of 
         them, but do not be surprised if they react adversely and try to     
         stop you. In fact, if at any point during the exercise you hear the  
         satanic voice of Bill Gates coming from the built-in speaker, take   
         off running and do not ever look back! Freed from the                
         counterbalancing influence of the BSD daemons, the twin demons of    
         DOS and Windows(R) are often able to re-assert total control over    
         your machine to the eternal damnation of your soul. Now that you     
         know, given a choice you would probably prefer to get used to the    
         scratchy noises, no?                                                 
   16.3. How many FreeBSD hackers does it take to change a lightbulb?         
         One thousand, one hundred and sixty-nine:                            
                                                                              
         Twenty-three to complain to -CURRENT about the lights being out;     
                                                                              
         Four to claim that it is a configuration problem, and that such      
         matters really belong on -questions;                                 
                                                                              
         Three to submit PRs about it, one of which is misfiled under doc and 
         consists only of "it's dark";                                        
                                                                              
         One to commit an untested lightbulb which breaks buildworld, then    
         back it out five minutes later;                                      
                                                                              
         Eight to flame the PR originators for not including patches in their 
         PRs;                                                                 
                                                                              
         Five to complain about buildworld being broken;                      
                                                                              
         Thirty-one to answer that it works for them, and they must have      
         updated at a bad time;                                               
                                                                              
         One to post a patch for a new lightbulb to -hackers;                 
                                                                              
         One to complain that he had patches for this three years ago, but    
         when he sent them to -CURRENT they were just ignored, and he has had 
         bad experiences with the PR system; besides, the proposed new        
         lightbulb is non-reflexive;                                          
                                                                              
         Thirty-seven to scream that lightbulbs do not belong in the base     
         system, that committers have no right to do things like this without 
         consulting the Community, and WHAT IS -CORE DOING ABOUT IT!?         
                                                                              
         Two hundred to complain about the color of the bicycle shed;         
                                                                              
         Three to point out that the patch breaks style(9);                   
                                                                              
         Seventeen to complain that the proposed new lightbulb is under GPL;  
                                                                              
         Five hundred and eighty-six to engage in a flame war about the       
         comparative advantages of the GPL, the BSD license, the MIT license, 
         the NPL, and the personal hygiene of unnamed FSF founders;           
                                                                              
         Seven to move various portions of the thread to -chat and -advocacy; 
                                                                              
         One to commit the suggested lightbulb, even though it shines dimmer  
         than the old one;                                                    
                                                                              
         Two to back it out with a furious flame of a commit message, arguing 
         that FreeBSD is better off in the dark than with a dim lightbulb;    
                                                                              
         Forty-six to argue vociferously about the backing out of the dim     
         lightbulb and demanding a statement from -core;                      
                                                                              
         Eleven to request a smaller lightbulb so it will fit their           
         Tamagotchi if we ever decide to port FreeBSD to that platform;       
                                                                              
         Seventy-three to complain about the SNR on -hackers and -chat and    
         unsubscribe in protest;                                              
                                                                              
         Thirteen to post "unsubscribe", "How do I unsubscribe?", or "Please  
         remove me from the list", followed by the usual footer;              
                                                                              
         One to commit a working lightbulb while everybody is too busy        
         flaming everybody else to notice;                                    
                                                                              
         Thirty-one to point out that the new lightbulb would shine 0.364%    
         brighter if compiled with TenDRA (although it will have to be        
         reshaped into a cube), and that FreeBSD should therefore switch to   
         TenDRA instead of GCC;                                               
                                                                              
         One to complain that the new lightbulb lacks fairings;               
                                                                              
         Nine (including the PR originators) to ask "what is MFC?";           
                                                                              
         Fifty-seven to complain about the lights being out two weeks after   
         the bulb has been changed.                                           
                                                                              
         Nik Clayton <nik@FreeBSD.org> adds:                                  
                                                                              
         I was laughing quite hard at this.                                   
                                                                              
         And then I thought, "Hang on, shouldn't there be '1 to document it.' 
         in that list somewhere?"                                             
                                                                              
         And then I was enlightened :-)                                       
                                                                              
         Thomas Abthorpe <tabthorpe@FreeBSD.org> says: "None, real FreeBSD    
         hackers are not afraid of the dark!"                                 
   16.4. Where does data written to /dev/null go?                             
         It goes into a special data sink in the CPU where it is converted to 
         heat which is vented through the heatsink / fan assembly. This is    
         why CPU cooling is increasingly important; as people get used to     
         faster processors, they become careless with their data and more and 
         more of it ends up in /dev/null, overheating their CPUs. If you      
         delete /dev/null (which effectively disables the CPU data sink) your 
         CPU may run cooler but your system will quickly become constipated   
         with all that excess data and start to behave erratically. If you    
         have a fast network connection you can cool down your CPU by reading 
         data out of /dev/random and sending it off somewhere; however you    
         run the risk of overheating your network connection and / or         
         angering your ISP, as most of the data will end up getting converted 
         to heat by their equipment, but they generally have good cooling, so 
         if you do not overdo it you should be OK.                            
                                                                              
         Paul Robinson adds:                                                  
                                                                              
         There are other methods. As every good sysadmin knows, it is part of 
         standard practice to send data to the screen of interesting variety  
         to keep all the pixies that make up your picture happy. Screen       
         pixies (commonly mis-typed or re-named as "pixels") are categorized  
         by the type of hat they wear (red, green or blue) and will hide or   
         appear (thereby showing the color of their hat) whenever they        
         receive a little piece of food. Video cards turn data into           
         pixie-food, and then send them to the pixies - the more expensive    
         the card, the better the food, so the better behaved the pixies are. 
         They also need constant stimulation - this is why screen savers      
         exist.                                                               
                                                                              
         To take your suggestions further, you could just throw the random    
         data to console, thereby letting the pixies consume it. This causes  
         no heat to be produced at all, keeps the pixies happy and gets rid   
         of your data quite quickly, even if it does make things look a bit   
         messy on your screen.                                                
                                                                              
         Incidentally, as an ex-admin of a large ISP who experienced many     
         problems attempting to maintain a stable temperature in a server     
         room, I would strongly discourage people sending the data they do    
         not want out to the network. The fairies who do the packet switching 
         and routing get annoyed by it as well.                               
   16.5. My colleague sits at the computer too much, how can I prank her?     
         Install games/sl and wait for her to mistype sl for ls.              

                          Chapter 17. Advanced Topics

   17.1. How can I learn more about FreeBSD's internals?

   17.2. How can I contribute to FreeBSD?

   17.3. What are snapshots and releases?

   17.4. Can I follow -CURRENT with limited Internet access?

   17.5. I have written a kernel extension, who do I send it to?

   17.6. How can I make the most of the data I see when my kernel panics?

   17.7. Why has dlsym() stopped working for ELF executables?

   17.8. How can I increase or reduce the kernel address space on i386?

17.1. How can I learn more about FreeBSD's internals?                             
      See the FreeBSD Architecture Handbook.                                      
                                                                                  
      Additionally, much general UNIX(R) knowledge is directly applicable to      
      FreeBSD.                                                                    
17.2. How can I contribute to FreeBSD?                                            
      Please see the article on Contributing to FreeBSD for specific advice on    
      how to do this. Assistance is more than welcome!                            
17.3. What are snapshots and releases?                                            
      There are currently 3 active/semi-active branches in the FreeBSD Subversion 
      Repository. (Earlier branches are only changed very rarely, which is why    
      there are only 3 active branches of development):                           
                                                                                  
        * stable/8/ AKA 8-STABLE                                                  
                                                                                  
        * stable/9/ AKA 9-STABLE                                                  
                                                                                  
        * head/ AKA -CURRENT AKA 10-CURRENT                                       
                                                                                  
      HEAD is not an actual branch tag, like the others; it is simply a symbolic  
      constant for "the current, non-branched development stream" which we simply 
      refer to as -CURRENT.                                                       
                                                                                  
      Right now, -CURRENT is the 10.X development stream; the 9-STABLE branch,    
      stable/9/, forked off from -CURRENT in September 2011 and the 8-STABLE      
      branch, stable/8/, forked off from -CURRENT in August 2009.                 
17.4. Can I follow -CURRENT with limited Internet access?                         
      Yes, you can do this without downloading the whole source tree by using the 
      CTM facility.                                                               
17.5. I have written a kernel extension, who do I send it to?                     
      Please take a look at the article on Contributing to FreeBSD to learn how   
      to submit code.                                                             
                                                                                  
      And thanks for the thought!                                                 
17.6. How can I make the most of the data I see when my kernel panics?            
      Here is typical kernel panic:                                               
                                                                                  
      Fatal trap 12: page fault while in kernel mode                              
      fault virtual address   = 0x40                                              
      fault code              = supervisor read, page not present                 
      instruction pointer     = 0x8:0xf014a7e5                                    
      stack pointer           = 0x10:0xf4ed6f24                                   
      frame pointer           = 0x10:0xf4ed6f28                                   
      code segment            = base 0x0, limit 0xfffff, type 0x1b                
                              = DPL 0, pres 1, def32 1, gran 1                    
      processor eflags        = interrupt enabled, resume, IOPL = 0               
      current process         = 80 (mount)                                        
      interrupt mask          =                                                   
      trap number             = 12                                                
      panic: page fault                                                           
                                                                                  
      When you see a message like this, it is not enough to just reproduce it and 
      send it in. The instruction pointer value is important; unfortunately, it   
      is also configuration dependent. In other words, the value varies depending 
      on the exact kernel image that you are using. If you are using a GENERIC    
      kernel image from one of the snapshots, then it is possible for somebody    
      else to track down the offending function, but if you are running a custom  
      kernel then only you can tell us where the fault occurred.                  
                                                                                  
      What you should do is this:                                                 
                                                                                  
       1. Write down the instruction pointer value. Note that the 0x8: part at    
          the beginning is not significant in this case: it is the 0xf0xxxxxx     
          part that we want.                                                      
                                                                                  
       2. When the system reboots, do the following:                              
                                                                                  
       % nm -n kernel.that.caused.the.panic | grep f0xxxxxx                       
                                                                                  
          where f0xxxxxx is the instruction pointer value. The odds are you will  
          not get an exact match since the symbols in the kernel symbol table are 
          for the entry points of functions and the instruction pointer address   
          will be somewhere inside a function, not at the start. If you do not    
          get an exact match, omit the last digit from the instruction pointer    
          value and try again, i.e.:                                              
                                                                                  
       % nm -n kernel.that.caused.the.panic | grep f0xxxxx                        
                                                                                  
          If that does not yield any results, chop off another digit. Repeat      
          until you get some sort of output. The result will be a possible list   
          of functions which caused the panic. This is a less than exact          
          mechanism for tracking down the point of failure, but it is better than 
          nothing.                                                                
                                                                                  
      However, the best way to track down the cause of a panic is by capturing a  
      crash dump, then using kgdb(1) to generate a stack trace on the crash dump. 
                                                                                  
      In any case, the method is this:                                            
                                                                                  
       1. Make sure that the following line is included in your kernel            
          configuration file (/usr/src/sys/arch/conf/MYKERNEL):                   
                                                                                  
       makeoptions     DEBUG=-g          # Build kernel with gdb(1) debug symbols 
                                                                                  
       2. Change to the /usr/src directory:                                       
                                                                                  
       # cd /usr/src                                                              
                                                                                  
       3. Compile the kernel:                                                     
                                                                                  
       # make buildkernel KERNCONF=MYKERNEL                                       
                                                                                  
       4. Wait for make(1) to finish compiling.                                   
                                                                                  
       5. # make installkernel KERNCONF=MYKERNEL                                  
                                                                                  
       6. Reboot.                                                                 
                                                                                  
        Note:                                                                     
                                                                                  
      If you do not use the KERNCONF make variable a GENERIC kernel will be built 
      and installed.                                                              
                                                                                  
      The make(1) process will have built two kernels.                            
      /usr/obj/usr/src/sys/MYKERNEL/kernel and                                    
      /usr/obj/usr/src/sys/MYKERNEL/kernel.debug. kernel was installed as         
      /boot/kernel/kernel, while kernel.debug can be used as the source of        
      debugging symbols for kgdb(1).                                              
                                                                                  
      To make sure you capture a crash dump, you need edit /etc/rc.conf and set   
      dumpdev to point to your swap partition (or AUTO). This will cause the      
      rc(8) scripts to use the dumpon(8) command to enable crash dumps. You can   
      also run dumpon(8) manually. After a panic, the crash dump can be recovered 
      using savecore(8); if dumpdev is set in /etc/rc.conf, the rc(8) scripts     
      will run savecore(8) automatically and put the crash dump in /var/crash.    
                                                                                  
        Note:                                                                     
                                                                                  
      FreeBSD crash dumps are usually the same size as the physical RAM size of   
      your machine. That is, if you have 512 MB of RAM, you will get a 512 MB     
      crash dump. Therefore you must make sure there is enough space in           
      /var/crash to hold the dump. Alternatively, you run savecore(8) manually    
      and have it recover the crash dump to another directory where you have more 
      room. It is possible to limit the size of the crash dump by using options   
      MAXMEM=N where N is the size of kernel's memory usage in KBs. For example,  
      if you have 1 GB of RAM, you can limit the kernel's memory usage to 128 MB  
      by this way, so that your crash dump size will be 128 MB instead of 1 GB.   
                                                                                  
      Once you have recovered the crash dump, you can get a stack trace with      
      kgdb(1) as follows:                                                         
                                                                                  
      % kgdb /usr/obj/usr/src/sys/MYKERNEL/kernel.debug /var/crash/vmcore.0       
      (kgdb) backtrace                                                            
                                                                                  
      Note that there may be several screens worth of information; ideally you    
      should use script(1) to capture all of them. Using the unstripped kernel    
      image with all the debug symbols should show the exact line of kernel       
      source code where the panic occurred. Usually you have to read the stack    
      trace from the bottom up to trace the exact sequence of events that lead to 
      the crash. You can also use kgdb(1) to print out the contents of various    
      variables or structures to examine the system state at the time of the      
      crash.                                                                      
                                                                                  
        Tip:                                                                      
                                                                                  
      Now, if you are really insane and have a second computer, you can also      
      configure kgdb(1) to do remote debugging such that you can use kgdb(1) on   
      one system to debug the kernel on another system, including setting         
      breakpoints, single-stepping through the kernel code, just like you can do  
      with a normal user-mode program.                                            
                                                                                  
        Note:                                                                     
                                                                                  
      If you have DDB enabled and the kernel drops into the debugger, you can     
      force a panic (and a crash dump) just by typing panic at the ddb prompt. It 
      may stop in the debugger again during the panic phase. If it does, type     
      continue and it will finish the crash dump.                                 
17.7. Why has dlsym() stopped working for ELF executables?                        
      The ELF toolchain does not, by default, make the symbols defined in an      
      executable visible to the dynamic linker. Consequently dlsym() searches on  
      handles obtained from calls to dlopen(NULL, flags) will fail to find such   
      symbols.                                                                    
                                                                                  
      If you want to search, using dlsym(), for symbols present in the main       
      executable of a process, you need to link the executable using the          
      --export-dynamic option to the ELF linker (ld(1)).                          
17.8. How can I increase or reduce the kernel address space on i386?              
      By default, the kernel address space is 1 GB (2 GB for PAE) for i386. If    
      you run a network-intensive server (e.g., a FTP or HTTP server), or you     
      want to use ZFS, you might find that is not enough.                         
                                                                                  
      Add the following line to your kernel configuration file to increase        
      available space and rebuild your kernel:                                    
                                                                                  
      options KVA_PAGES=N                                                         
                                                                                  
      To find the correct value of N, divide the desired address space size (in   
      megabytes) by four. (For example, it is 512 for 2 GB.)                      

                          Chapter 18. Acknowledgments

   This innocent little Frequently Asked Questions document has been written,
   rewritten, edited, folded, spindled, mutilated, eviscerated, contemplated,
   discombobulated, cogitated, regurgitated, rebuilt, castigated, and
   reinvigorated over the last decade, by a cast of hundreds if not
   thousands. Repeatedly.

   We wish to thank every one of the people responsible, and we encourage you
   to join them in making this FAQ even better.

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