As of the latest release (v0.40), my TMDA SPAM reduction software now
supports Exim in addition to Postfix and qmail.
TMDA is an OSI certified software application designed to
significantly reduce the amount of SPAM/UCE you receive. TMDA
combines a "whitelist" (for known/trusted senders), a "blacklist"
(for undesired senders), and a cryptographically enhanced
confirmation system (for unknown, but legitimate senders). TMDA
strives to be more effectual, yet less time-consuming than
traditional filters.
For more information including a demonstration, download locations and
installation instructions, visit the TMDA homepage:
<URL:
http://tmda.sourceforge.net/>
Enjoy.