Description:

Mailfilter is a flexible utility for Unix (-like) operating systems to
get rid of unwanted spam mails, before having to go through the
trouble of downloading them into the local computer. It offers support
for one or many POP3 accounts and is especially useful for dialup
connections via modem, ISDN, etc.
Mailfilter connects to any POP3 mail box and compares part of its
content to a set of user defined filter rules. That way the spam gets
deleted directly on the mail server.