Postfix [http://www.postfix.org/] is a very good unix MTA (mail transport agent) ... mailserver :)

'''How to use tcl with Postfix''' - 20040608 [CMcC]

I had an application called elink, which needed to process incoming email under tcl.

'''First:''' Add a new Postfix ''transport'' to /etc/postfix/master.cf:

    elink     unix  -       n       n       -       -       pipe flags=R user=elink:mail argv=/usr/bin/tclsh /home/elink.tcl $sender $nexthop $user $extension

This mail transport causes Postfix to open a unix pipe with a tclsh running the file /home/elink.tcl for each incoming email which uses the elink transport.  '''pipe''' [http://www.postfix.org/pipe.8.html] is a Postfix program which launches the tclsh with the appropriate perms and the appropriate mail values substituted on the command line for Postfix's variables (''$user'' etc.)

'''Next:''' you have to specify when the transport (''elink'' in this example) it so be used to deliver email.

The details are hazy, but IIRC you specify which addresses or domains are to be transported by the specified transport in /etc/postfix/transport like this:

    user+extension@domain transport:nexthop
    .domain transport:nexthop

You'll have to at least read Postfix documentation to be able to cobble together a mailing list manager in tcl.
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