bftpd documentation
  originally written by Max-Wilhelm Bruker <brukie@gmx.net>
  currently maintained by Jesse Smith <jessefrgsmith@yahoo.ca>


  This document is the documentation for the bftpd FTP server.
  ______________________________________________________________________

  Table of Contents


  1. Introduction
  2. Installation
     2.1 Compiling
     2.2 Running the server

  3. Configuration
     3.1 User management
     3.2 The configuration file
        3.2.1 The global structure
        3.2.2 User structures
        3.2.3 Group structures
        3.2.4 Directory structures

  4. FAQ
     4.1 Problems while compiling
        4.1.1 I can't compile bftpd
        4.1.2 There are strange warnings
        4.1.3 Make tells me I can't use wtmp
     4.2 Problems when trying to run it
        4.2.1 I get a warning like "Could not get peer IP address."
        4.2.2 I get an error like "Bind failed: Address already in use."
     4.3 Problems during the FTP sessions
        4.3.1 I get an error like "500 Unknown command: 'foo'"
        4.3.2 The session terminates with a 421 error
     4.4 Miscellaneous
        4.4.1 How does the on-the-fly compression work?
        4.4.2 My options for an anonymous user don't work
        4.4.3 Why is there so little documentation?
     4.5 Logging
        4.5.1 What information is logged?
        4.5.2 How can I get bandwidth usage information?


  5. Credits
     5.1 Portability testing
     5.2 Suggestions, bug reports & code contributions
     5.3 Documentation contributions
     5.4 Others


  ______________________________________________________________________

  1.  Introduction

  bftpd is an FTP server for Linux, BSD/OS, FreeBSD, Solaris, DG-UX and
  Tru64. (I don't know if it runs on other systems, please mail me if
  you have tried it). It runs either with inetd or standalone.

  It tries to be very configurable while being fast and small. You can
  make defaults for each configuration option, and then override these
  defaults in user-specific and directory-specific structures.

  Features of bftpd include:

  +o  Easy configuration

  +o  Speed

  +o  Support for most RFC FTP commands

  +o  tar.gz on-the-fly compression/archiving

  +o  Security with chroot without special setup

  +o  No need for files (sh, ls...) in a chroot environment

  +o  Logging to wtmp and to a logfile or syslog

  +o  PAM and passwd/shadow support

  +o  Support for SITE CHOWN/CHMOD

  2.  Installation

  2.1.  Compiling

  First execute the following commands (replacing x.x.x by the version
  number you are installing):


       tar xzf bftpd-x.x.x.tar.gz
       cd bftpd-x.x.x
       ./configure
       make
       make install



  Note that you have to copy bftpd.conf from the source directory to
  /etc manually if you are upgrading from a previous version, as 'make
  install' does not overwrite your existing configuration.

  Note: If you want to use the 'tar.gz on-the-fly' feature of bftpd, you
  must grab the source code of the program "pax" and extract it into a
  subdirectory of the bftpd source directory. Then, instead of doing
  "./configure", do "./configure --enable-pax=pax-sourcedir --enable-
  libz".  You must also have the library libz and its header file,
  /usr/include/zlib.h.

  2.2.  Running the server

  bftpd runs in either standalone or inetd mode.

     If you want inetd mode
        Add the following to your /etc/inetd.conf:


          ftp stream tcp nowait root /usr/sbin/bftpd bftpd



     Give inetd a HUP or reboot your system. Your FTP server should work
     now.

     If you want inetd mode with xinetd
        Add the following to your /etc/xinetd.conf:



     service ftp
     {
         disable = no
         socket_type             = stream
         wait                    = no
         user                    = root
         server                  = /usr/sbin/bftpd
         log_on_success          += HOST PID
         log_on_failure          += HOST
         nice                    = 10
     }



     (contributed by JackRipper)

     If you want standalone mode:
        Make the OS execute


          /usr/sbin/bftpd -d



     at bootup.

  3.  Configuration

  3.1.  User management

  You can manage the users simply by editing /etc/passwd and, if your
  system supports it, /etc/shadow. Any user existent in /etc/passwd can
  connect to the FTP server if he has a usable password and meets
  certain configurable criteria. Having anonymous users is possible by
  setting a configuration variable called ANONYMOUS_USER to yes. PAM is
  also supported.

  3.2.  The configuration file

  3.2.1.  The global structure

  In the "global" structure, you can assign values to configuration
  options. The syntax is like the following:


       global {
         name1="value1"
         name2="value2"
       }



  3.2.2.  User structures

  There are also user structures, in which you can override the global
  settings for particular users. Example:



  global {
    name1="value1"
    name2="value2"
  }
  user foo {
    name1="value3"
  }



  If the user foo is logged in, name1 will be value3. If another user is
  logged in, name1 will be value1. name2 is always value2.

  3.2.3.  Group structures

  You can also define options for groups of users. It is just as it
  would be for one user, but you can put more than one user in a group.
  You can also put system groups into them by using the @ character.
  Example:


       group foo,bar,@baz {
         name1="value1"
       }



  This options affect the users foo and bar and every user who is in the
  system group baz. A supplementary membership is sufficient.

  3.2.4.  Directory structures

  You can set options which affects only the users who are in a certain
  directory, or in any subdirectory of it, recursively. Note that you
  must put these structures 4minside24m the global, user and group
  structures. This way, you can also override directory-specific
  settings for particular users. Example:


       global {
         name1="value1"
         directory "/foo" {
           name1="value2"
         }
       }
       user bar {
         directory "/foo" {
           name1="value3"
         }
       }



  In this example, name1 will be value3 if the user bar is in the direc-
  tory /foo. It will be value2 if another user is in the directory /foo.
  In any other case, it will be value1.

  An explanation of the name/value pairs is in the example configuration
  file supplied with bftpd (if you are not upgrading, this file has
  already been copied to /etc on your system). Modify it so that it fits
  your needs. The defaults should be OK though.


  4.  FAQ

  4.1.  Problems while compiling

  4.1.1.  I can't compile bftpd

  Let me know. Please tell me what architecture and operating system you
  are using, and give me the output of the complete compilation process
  (configure and make). I don't get a lot of mail, so I'll try to answer
  your questions. If I don't reply, I have almost certainly forgotten
  your mail, so please send it again :)

  4.1.2.  There are strange warnings

  It is likely that compiling bftpd on a platform I haven't tested may
  give you some warnings. Even if it compiles successfully and runs
  without crashing, please tell me, as compiler warnings 4mcan24m cause
  problems which are not obvious.

  4.1.3.  Make tells me I can't use wtmp

  You are probably running Solaris. As I don't have access to a Solaris
  computer, I have never been able to test the wtmp functions in it. If
  you get a warning like this and you don't know what wtmp is, just
  don't worry about it, or else help me to fix the error.

  4.2.  Problems when trying to run it

  4.2.1.  I get a warning like "Could not get peer IP address."

  You have started bftpd on the console. If you want to run it as a
  standalone server, you have to invoke it with the "-d" option. If you
  have set it up as an inetd server, you can test it with:


       hostname:~$ ftp localhost



  4.2.2.  I get an error like "Bind failed: Address already in use."

  This error means that another process has bound itself to the port you
  want to run bftpd on. You can set this port in bftpd.conf with the
  option PORT in the global structure. It defaults to 21. If you have
  not changed that, you probably forgot to turn off your old FTP server.
  Look in /etc/inetd.conf and in "ps auxwww | grep ftp".

  4.3.  Problems during the FTP sessions

  4.3.1.  I get an error like "500 Unknown command: 'foo'"

  Your client has sent a command to the server which it didn't
  understand. This is my fault, unless you have written a really
  inexistent command. Please check your command for typographic errors
  and report the error to me if you are sure that the command was right.

  4.3.2.  The session terminates with a 421 error

  If you try to log in with a wrong password, bftpd will terminate the
  connection. If you already had logged in before the error appeared, or
  the error appeared before you could log in, it definitely is a bug.
  Please tell me everything about it.



  4.4.  Miscellaneous

  4.4.1.  How does the on-the-fly compression work?

  Let's say you have a directory called foo. Even if there is no file
  called foo.tar.gz, you can RETR this file over FTP and it will contain
  the contents of the directory foo, tar-gzipped. You can also RETR the
  following files:

  +o  dirname.tar

  +o  filename.gz

     If you want to use this, you must compile it in (see the
     installation section).

  4.4.2.  My options for an anonymous user don't work

  If you have a structure with an ALIAS=... in it, you mustn't put any
  more options in it. Instead, put them into the structure the alias
  points to.

  4.4.3.  Why is there so little documentation?

  The answer is simple, nobody has written anything
  I never know what to write, so if you have any idea of how to improve
  the documentation, please tell me. The same applies to translations of
  documentation. If you want to contribute something, write it out and
  e-mail it to me.


  4.5.1.  What information is logged?

  By default, information is logged to /var/log/bftpd.log. This file contains
  records of failed logins and successful logins, including the client's IP
  address and username. Session timeouts are logged, as are file uploads and
  downloads. Sessions where the client decides to quit are also logged.
  Each log entry includes the time, date and process ID of the server to
  help you track down problems.


  4.5.2.  How can I get bandwidth usage information?

  As of bftpd version 2.5, the server has the option of logging bandwidth usage.
  To use this feature, set the option BANDWIDTH in bftpd.conf to point to a valid
  directory on the server. By default, bandwidth usage is not logged.
  After each file transfer (upload or download) the server will save the amount of
  data transferred in a log file. Let's say you set the BANDWIDTH variable to point to "/var/log/bftpd",
  the server will keep a log of transfers in a file for each day. So if the client
  connects on December 20, 2009, the file will be called /var/log/bftpd/2009-12-20.txt.
  If another client connects on December 21, 2009, the file will be called /var/log/bftpd/2009-12-21.txt.
  Now, how do you make use of that data?
  Let's say you want to get bandwidth usage for everyone for Dec 20, 2009. You could use
  this command:

  cat /var/log/bftpd/2009-12-20.txt | awk 'BEGIN {down=0; up=0} {down = down + $2; up = up + $3} END {print "Download: " down  " -- Uploaded: " up}'

  But if you wanted to get usage information for just one user, you could do this:

  cat /var/log/bftpd/2009-12-20.txt | grep myusername | awk 'BEGIN {down=0; up=0} {down = down + $2; up= up + $3} END {print "Download: " down  " -- Uploaded: " up}'

  To get the usage information for one user for the month of December, you could use:

  cat /var/log/bftpd/2009-12-* | grep myusername | awk 'BEGIN {down=0; up=0} {down = down + $2; up= up + $3} END {print "Download: " down  " -- Uploaded: " up}'


   Please note that the bandwidth usage logs should be rotated just like any other log to avoid filling up the server's disk.




  5.  Credits

  5.1.  Portability testing


  +o  David L. Nicol (david@kasey.umkc.edu) tested bftpd on Tru64.

  +o  JackRipper (vic@altoona.net) tested bftpd on BSD/OS and DG-UX.

  +o  Christian Beyerlein (christian@beyerlein.de) tested bftpd on
     FreeBSD and Solaris.

  +o  The people from #linux (IRCNet) tested bftpd on various operating
     systems.

  5.2.  Suggestions, bug reports & code contributions


  +o  Josh Woodcock (josh@hamparts.com) gave some hints about Solaris 8.

  +o  Floh (floh@maflohsoft.de) suggested the ASCII mode support.

  +o  Erik Hensema (erik@hensema.xs4all.nl) found a Linux 2.4.0 netfilter
     bug which affected bftpd.

  +o  Heiko Rother (rother@cmsnet.de) suggested a lot of things (see
     changelog).

  +o  Christophe Bailleux (cb@grolier.fr) loves to find problems in the
     directory listing routines. He also suggested a lot of things and
     contributed some code.

  +o  Jonathan Heusser (jonathanheusser@gyml.unibas.ch) found a buffer
     overflow bug.


  +o  Christian Beyerlein (christian@beyerlein.de) suggested to make user
     aliases.

  +o  Elmusafir (jslmarti@campus.cem.itesm.mx) reported the StarOffice
     problem fixed in 1.0.8.

  +o  Alex Madden (alexm@immstudios.com) and Daniel Mack
     (daniel.mack@nextra.de) reported the Solaris incompatibility fixed
     in 1.0.8.

  +o  Daniel Mack (daniel.mack@nextra.de) contributed a big patch (see
     changelog).

  5.3.  Documentation contributions


  +o  Radek Michalski (radek@end.p-s.com.pl) translates the bftpd docs
     into Polish and also contributes new text.

  5.4.  Others


  +o  Some ideas about code structure and portability where taken from
     betaftpd bei Steinar H. Gunderson. But these were only a few lines!