Alan Schwartz 
SpamAssassin [PDF ebook] 
The Open Source Solution to SPAM

The annoyance factor for individual users whose email is crammed with pitches for pornography, absurd moneymaking schemes, and dubious health products is fierce. But for organizations, the cost of spam in lost productivity and burned bandwidth is astronomical. While society is grappling with a solution to the burgeoning crisis of spam proliferation, the pressure is on system administrators to find a solution to this massive problem in-house. And fast.Sys admins can field scores of complaints and spend months testing software suites that turn out to be too aggressive, too passive, or too complicated to setup only to discover that Spam Assassin (SA), the leading open source spam-fighting tool, is free, flexible, powerful, highly-regarded, and remarkably effective. The drawback? Spam Assassin’s lack of published documentation.Spam Assassin by Alan Schwartz, is the only published resource devoted to Spam Assassin and how to integrate it effectively into your networks. This clear, concise guide clarifies the installation, configuration, and use of the Spam Assassin spam-checking system (versions 2.63 and 3.0) for Unix system administrators using the Postfix, Sendmail, Exim, or qmail mail servers, helping administrators make the right integration decision for their particular environments.It covers concrete advice on how to:Customize Spam Assassin’s rules, and even create new ones Train Spam Assassin’s Bayesian classifier, a statistical engine for detecting spam, to optimize it for the sort of email that you typically receive Block specific addresses, hosts, and domains using third-party blacklists like the one maintained by Spamcop.net.Whitelist known good sources of email, so that messages from clients, coworkers, and friends aren’t inadvertently lost.Configure Spam Assassin to work with newer spam-filtering methods such as Hashcash (www.hashcash.org) and Sender Policy Framework (SPF).Sys admins, network administrators, and ISPs pay for spam with hours of experimentation and tedious junk email management, frayed user tempers, and their sanity. Spam Assassin, together with this essential book, give you the tools you need to take back your organization’s inboxes."Detailed, accurate and informative–recommended for spam-filtering beginners and experts alike." –Justin Mason, Spam Assassin development team