NAME

   pop3filter - POP3 Transparent Proxy with filters support


SYNOPSIS

   pop3filter [-hvf] [-e file] [--help] [--version] [--fork]
          [--listen
] rhost remoteport lport [ filter ]



ARGUMENTS

   rhost
          remote host to connect (the POP3 server)
   remoteport
          remote port to connect (usually 110)
   lport
          local port to bind and listen
   filter
          program that will filter the messages. If none is selected the
          message is left as-is



OPTIONS

   -h or --help
          display the help and exit
   -V or --version
          print version information and exit
   -f or --fork
          fork to the background
   -e file
          Append filter stderr output to file
   --listen 

          bind only to the interface address
   --user 
          run server as user 
   --group 
          run server in group 



FILTERS

   TODO

   The following enviroment variables are defined in the enviroment of
   the filter process:

   POP3_USERNAME
          The POP3 username. Eg. bob
   POP3_SERVER
          The POP3 server. Eg: pop3.isp.net
   POP3_RPORT
          The server's port. Eg: 110
   POP3_LPORT
          Local opened port. Eg: 11011
   POP3_VERSION
          Version of pop3filter. Eg: 0.0.1



NOTES

   When you kill the server (when running as a stand alone server) the
   child process (active clients) are not killed so they can finish their
   transaccions. I found this like a good behavior. Tell me your opinion
   if you do not agree.


EXAMPLES

   I assume that the POP3 server that we want to proxy is at pop3.isp.net
   at the port 110.

   *
          Say you want just to set up the proxy at the port 11011 with no
          filter.
               AMPLE
   *
          Now you want to catch all request on your network going to
          pop3.isp.net so the thing goes transparent. If you use Linux()
          2.4, with Netfilter:
               AMPLE
   *
          Now you want to leave the program running as a daemon?
               AMPLE
   *
          Lets do some filtering. Filter can be another file or just an
          `in-line'   expression:
               AMPLE
          (yes. nobody wants to do that, but is just an example)
   *
          Want to add some anti-spam header and rename dangerous
          attachments? You can use a filter something like:
               AMPLE
   *
          This program runs also from inetd. All errors and information
          goes to syslog. In your inetd.conf put something like:
               AMPLE
          Note that the filter can be called several times at the same
          time (multiple connections from different clients, so if you
          are writing things to a file use some sort of lock. Backup the
          message in an mbox and maildir format is left as exercise. I
          probably must add them here.



USEFULL TOOLS

   RenAttach
          Renattach is a small, efficient and surprisingly effective
          filter designed primarily to offer an additional level of
          safety to Windows users whose e-mails pass through a UNIX-like
          mail server. Many modern viruses are spread through e-mail, and
          renattach combats such viruses by filtering e-mail attachments
          based on file extension.
          [3]http://www.pc-tools.net/linux/
   DSPAM
          SPAM (as in De-Spam) is an extremely scalable, open-source
          statistical hybrid anti-spam filter. While most commercial
          solutions only provide a mere 95% accuracy (1 error in 20), a
          majority of DSPAM users frequently see between 99.95% (1 error
          in 2000) all the way up to 99.985% (1 error in 7000). DSPAM is
          currently effective as both a server-side agent for UNIX email
          servers and a developer's library for mail clients, other
          anti-spam tools, and similar projects requiring drop-in spam
          filtering. DSPAM has been implemented on many large and small
          scale systems with the largest systems being reported at about
          125,000 mailboxes.
          [4]http://www.nuclearelephant.com/projects/dspam/
   SpamAssasin
          SpamAssassin is a mail filter to identify spam. Using its rule
          base, it uses a wide range of heuristic tests on mail headers
          and body text to identify "spam", also known as unsolicited
          commercial email.
          [5]http://spamassassin.taint.org/
   ripMIME
          Let you get all the parts of a MIME message (that means also
          get the files) With this one you can use an anti-virus.
          [6]http://pldaniels.org/ripmime/
   TNEF
          TNEF decodes those annoying MS-TNEF MIME attachments that
          Microsoft mail servers helpfully use to encapsulate your
          already MIME encoded attachments.
          [7]http://world.std.com/~damned/software.html
   BASE64
          BASE64 (RFC 1341) Encoder/Decoder that i wrote some years ago.
          Very simple.
          [8]http://www.ibiblio.org//pub/Linux/system/mail/base64-1.1.tar
          .gz
          Tell me if you want a pointer to your filter!



BUGS

   See the BUGS file in the distribution or go to Bug the Tracking Site


AUTHOR

   Original written by Juan F. Codagnone <[9]juam@users.sourceforge.net>


COPYRIGHT

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   under the terms of the GNU Free Documentation License, Version 1.1 or
   any later version published by the Free Software Foundation; with the
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