SpamAssassin
SpamAssassin uses a wide variety of local and network tests to eradicate SPAM from your inbox:
- Heuristics Engine - Thousands of tests check the message headers and content for tell tale signs of spam. The originating mail server and senders address are verified to prevent spoofing.
- Bayesian Probability Algorithms - Bayesian algorithms are used to build up a database of the characteristics of unwanted mail and the characteristics of legitimate mail. The database can then be consulted to determine the likelihood of any particular message being spam. Furthermore, through continually analysing messages the database is actively updated as the nature of spam changes, creating a form of self evolving intelligence.
- Checksum Databases - Any message has a unique checksum, as users report unsolicited mail messages, their checksums are added to a database. Several collaborative checksum databases are consulted to ascertain whether the message concerned matches one previously identified as spam by another internet user.
- Real Time Blackhole Lists - Several real time blackhole lists (RBLs) are maintained on the internet which catalog known sources of spam. SpamAssassin checks for the presence of the originating mail servers in any of these lists.
Each positive test assigns a weighted score to the incoming message. The final score is used to determine whether or not the message is spam. This scoring system combined with the quantity and diversity of tests performed means that the likelihood of SpamAssassin incorrectly identifying a message as spam is negligible and makes it nigh on impossible for spammers to craft their messages to bypass the filters.
SpamAssassin may be controlled via your control panel; there is no limit to the number of mailboxes you may protect with SpamAssassin.