sendmail Milters : A Guide for Fighting Spam

Rating:
Summary: Good Even if You're Not Using Sendmail
Review: As the title says, the bulk of this book is on working with spam on the sendmail software package. If you are using sendmail, there is no question that this is the book for you.

The strange thing is, that there is so much information on spam contained in this book that I'd recommend it even if you are using some other software package. The general discussion on spam, its history, its impact on the industry and on individuals, and especially on it's techniques of spammers.

I particularly enjoyed his philosophy of setting up a Bait Machine just to collect inbound spam. He then began developing techniques to stop the spam that was coming to the bait machine. Great concept.

Rating:
Summary: very good spam descriptions
Review: In the ongoing struggle against spam, adding filters to sendmail is a vital ability. Sendmail is probably the most common mail transfer agent on the Internet. The book describes how the latest sendmail supports a Milter interface. So that you, as a sysadmin or programmer, can write a program, usually in C, that implements a filter of your choice.

There has been various documentation on how to do this. Often scattered throughout the Web, and at various levels of competence and detail. But finally here, we have an entire book devoted to comprehensively explaining Milter.

It should be said that the authors deliberately don't go into details of what filters you might write. That is an open ended topic which is properly your remit, not theirs.

But as a bonus, there is a superb chapter on spam. It concisely goes into explaining techniques spammers use to obfuscate their mail. You can find out why blocking spam on the basis of checking subjects is essentially useless, for example. The chapter describes methods that other books on spam rarely go into. Actually, even if you have no intention of using Milter, you may want to consider the book for this chapter alone.