SpamAssassin is one of the best-known Open Source spam filters. It is now an Apache Foundation project. The main advantage of SpamAssassin is that it integrates many different types of tests – each test adds to or subtracts from the message's "spaminess", and the message gets a final score that combines all the tests. The primary disadvantage of SpamAssassin is that it is relatively slow, because it is written in Perl and runs through a large number of tests. We believe that our boxes are plenty powerful enough to handle the load, especially with some of the Postfix spam-avoidance techniques (such as greylisting) that reduce the number of spam emails that make it into the system.

All SpamAssassin settings are global in nature and not settable on a per user basis. This is the reason that we set the delete threshold so high – some users may want a higher threshold than others. Those that want a lower threshold can do so using procmail filters (or whichever other delivery agent we choose). Those wanting special rules will also have to set them up as procmail filters.

This will be integrated into the mail flow via the MailScanner software which will be installed from the mailscanner deb package. (More info can be gotten from http://www.mailscanner.info/)