Slamming Spam: A Guide for System Administrators

Chapter 3. SpamAssassin

In this chapter, we introduce SpamAssassin, which is a widely used interface to other anti-spam mechanisms as well a spam classifier in its own right. SpamAssassin has its own rules base, which is used to assign a “score” to each mail message. The methods SpamAssassin uses to classify whether email is spam are as follows:

• Header analysis— SpamAssassin can analyze these headers of an email message and generate a score based on them.

• Body analysis— The body of a spam message often contains phrases (i.e., “Reduce your debt!”) that can easily identify it as spam.

• Bayesian analysis— Bayes is a statistical methodology where both the headers and body of a message are compared against a known database of phrases. This book dedicates ...