Removing The Spam. Email Processing and Filtering

reviewed by Bob Bruen

by Geoff Mulligan. Addison-Wesley. 1999.
190 pages. Index. Appendix. $19.95.
ISBN 0-201-37957-0 LoC TK5105.73.M85.

Removing The Spam assumes that spam is something undesirable, so there is little effort made to convince the reader to conform to this point of view. Instead Mr. Mulligan provides a straight forward, in depth explanation of how electronic mail works. Armed with this information one can take action keep spam out of the bit stream.

There are only four chapters in the book: 1) The Dawn of Electronic Mail, 2) Sendmail, 3) Procmail and 4) Mailing Lists. The appendix is fifteen pages of web sites, mailing lists, RFCs and other useful resources. The book is really more about the intricacies of email and how to administer mail and less about spam, which makes the book a valuable resource, for example, to get Sendmail up and running.

If you are new to managing email on a Unix system, this book is well worth $20 because it gives a clear introduction to filtering using Procmail and managing mailing list using Majordomo, Listproc, Smartmail and even Sendmail. The pros and cons of each are presented without obvious bias making your choice a bit easier. The source sites for each of them, the steps to build to them and the day to day management issues are included. In the end, of course, the procedures for removing spam with each are highlighted.

Sendmail is a fairly complex piece of software that many sysadmins can successfully ignore. This chapter gets you past the mystique with a simple explanation of how to get, set up and do elementary configuration changes. Since no experienced sysadmin can really get by without mastering Sendmail, reading this chapter will serve as a good introduction before you tackle the real Sendmail book.

Procmail as a filtering agent gets its own chapter with examples of the recipes and rc files to filter mail. There is certainly enough detail here to get you actually filtering email even if you have never heard of Procmail. The focus of the filtering is for spam, but the examples include steps for making the mail you want to get, easier to get.

Because the approaches and coverage is different, I see this book as more of a companion rather than a competitor to Stopping Spam by Schwartz and Garfinkel. Each book takes a small topic, spam, and makes a book out of it by adding related material. S & G chose to add lots of text about how bad spam is, accompanied by activist resources and methods to stop it, including legal information. Mulligan has chosen to spend most of his attention on mastering the software that controls all aspects of email so that the tools are available to protect your own site. The resources listed in each book overlap, but they are different lists. Fortunately each costs less than $20. Buy both. The value added by each is worth it and the goal is the same.