Mailfilt is a perl script that filters incoming mail based upon a set
of rules defined in a .rules file. The location of that file and
the mail directory in which to put messages are specified at the
beginning of Mailfilt itself. The default directory is $HOME/mail.
The .rules file has a very rich syntax but is formatted like a makefile.
The following shows a sample .rules file that illustrates many of the
features:
PGP
Mailfilt has built-in support for PGP signatures. When it encounters a
PGP signed message, it will attempt to run pgp to authenticate
the message. For this to work properly, pgp must be in one of the
directories in the PATH statement in the configuration section of the
Mailfilt code and your public keyring must be in the directory pointed
to by the PGPPATH statement.
The signature block will appear in the message as it was sent, but
following the END SIGNATURE marker, a couple lines will be inserted
showing whether pgp could authenticate the message.
Users without pgp can use mailfilt without problem, except that an
error message will appear in the logfile each time a signed message is
received.
Example .rules file:
/dev/null:
Subject: this is junk
jimbob@the.farm: #Forward this stuff to Jim Bob
Subject: Farm report
&!From: jimbob
|/usr/bin/handle-cronmail:
From: root
&Subject: ^cron #Subject must start with cron
bulk:
Rcpt: biglist@alma.matter #biglist must be in To: or Cc:
personal: #Stuff addressed to either of my mail aliases
To: myname@big.fast.computer
To: myothername@big.fast.computer
primary: #Anything that hasn't already matched will go to this file
In this example, mail with this is junk in the subject will go to
/dev/null. Mail with Farm report in the subject that doesn't come
from jimbob will be mailed to jimbob@the.farm. Mail from root
with cron in the subject line will be put in the file bulk in the
mail directory. Mail that has biglist@alma.matter in the To: or Cc:
lines will also be put in bulk. Anything that hasn't met the above
criteria and that has myname@big.fast.computer in the To: line will be
put in the file personal in the mail directory. Finally, everything
else will be put in the file primary. This means that nothing will
end up in /var/spool/mail.
Some general rules to remember:
The first rule that matches is the one used.
Mail will only be forwarded once (to prevent looping)
Searches are in regex format (substring unless special operators given)
All matches are case-insensitive
Rcpt: is the combination of To: and Cc:
Filenames are in the mail directory unless they begin with a slash
If a message doesn't match any rules, it will be placed in
/var/spool/mail
Logical ORs are accomplished using multiple sets of criteria under a
single destination---see the "personal" block in the example above.
Last Modified at 09:53:32 on 24 July 95