"Thanasis Kinias" <tkinias@kinias.org> wrote in message news:20070830163747.GB5698@corbeau...
I was curious about this myself, so I checked <URL:http://www.gnu.org/software/anubis/manual/html_mono/anubis.html>: # GNU Anubis is an SMTP message submission daemon. Its purpose is to # receive the outgoing message, perform some manipulations over its # contents, and to forward the altered message to the mail transport # agent. That sounds like it's something like procmail in reverse: it figures out what to do with _outgoing_ messages based on rules. That sounds quite useful for users of wireless networks, for example, who have to do very creative configuration of their MTAs to deal with different relays based on which WLAN they're on at the moment... I haven't used this but I think it sounds eminently useful, frankly.
The gentoo short package description is "an outgoing mail processor".That seems to fit what you found, and may better convey the purpose of the package. I recommend you consider adopting it as the short description of your package.
But basically you are right. It sits between your MUA (email client) and your MTA (sendmail). It manipulates the message acording to rules, and then sends them on.
It is almost the exact oposite of procmail and maildrop. I think acts like an SMTP server to the mail clients, so that it gets the mail, and then it does the processing and passes it to the MTA. (Technically, it is a MSA (mail submision agent) which is something that takes mail, potentially does something with it, and passes it to an MTA.)