SpamAssassin is a mail filter to identify spam. See http://SpamAssassin.org/ for more details.

This flexible and powerful set of Perl programs, unlike older spam filtering approaches, uses the combined score from multiple types of checks to determine if a given message is spam.

Its primary features are:

• Header tests
• Body phrase tests. For more information, see SpamAssassinRules.
• Bayesian filtering (BayesFaq)
• Automatic address whitelist/blacklist (AutoWhitelist)
• Manual address whitelist/blacklist (ManualWhitelist)
• Collaborative spam identification databases (DCC, Pyzor, Razor2). See NetworkTests.
• RBL (Realtime Blackhole Lists)
• Character sets and locales

Even though any one of these tests might, by themselves, mis-identify a ham or spam, their combined score is terribly difficult to fool.

A documentation how to install SpamAssassin can be found on http://www.konabi.de .