Learn about SpamAssassin, a free email spam filter.
As part of the Apache Foundation, SpamAssassin is an open source and free application designed to filter spam in email and servers. This application is available for OS X, Windows, and Linux servers from the Apache Foundation SpamAssassin website.
SpamAssassin uses various Perl programs to identify incoming spam. They are designed for a certain amount of redundancy and complementary function to reduce misidentification.
SpamAssassin uses heuristics, or pattern recognition, to identify spam. As a result, a new installation it may block non-spam emails during an initial “learning” period.