The lack of a good guide to operating sendmail, the mail transport program routinely distributed with most forms of UNIX, has long been a sore point among network administrators. This book nicely fills that need.

The book is structured in three parts. The first part is a tutorial introduction (15 chapters), which explains the basics of sendmail by walking the reader through writing a simple configuration file (sendmail.cf). The tutorial is well written and makes developing a configuration file seem almost easy. This is no mean feat given that the intelligibility of sendmail configuration files has been compared unfavorably to that of modem line noise. (The syntax is heavy on one-character names, and the parsing rules change on a line-by-line basis.)

The second part (7 chapters) is devoted to administrative issues like domain name system (DNS) configuration, mailing list administration, and security. Pages 292 through 294 are particularly notable for clearly explaining how to properly set up a mailing list so that errors on email lists go to the person maintaining the list instead of the person who sent the mail that produced the error.

The third part (11 chapters, and roughly half the book) documents the details of how sendmail and its configuration rules work. These chapters appear to be exhaustive.

I found only a few important errors. The definition of fully qualified domain name on page 74 is not quite correct. A fully qualified domain name may be an MX destination that is not a hostname. In general, the book is a bit sloppy in distinguishing between domain names and host names. Appendix E mentions the .CSNET domain. CSNET was decommissioned a few years ago, and the .CSNET domain was eliminated long before CSNET was decommissioned. It also would have been nice if a chapter with guidelines for hub configuration files had been provided. In the scheme of things, however, these complaints are minor given the book’s tremendous usefulness to anyone maintaining sendmail.