There is no doubt that sendmail is one of the more complex systems a typical Unix system administrator is likely to have to deal with; my first glance at a sendmail.cf file was certainly off-putting. Leaving aside whether this isn't an argument for using a different MTA entirely, it certainly makes sendmail documentation important. The O'Reilly Sendmail book opens with a slow-paced 190 page tutorial, designed to put the faint-hearted at ease. This goes through the construction of a simple cf file, illustrating the workings of rulesets, macros, and workspaces. Next are sections on installation and configuration — compiling sendmail from source, using M4 to create config files, using checkcompat() — and on administration — covering interaction with the DNS, security, the mail queue, aliases, .forward files and mailing lists, and logging.

This is excellent stuff for people like me, seeking a basic understanding of how sendmail works and a guide to simple administration tasks. There may not be much in it for serious gurus, but they will appreciate the second half of Sendmail, which is a detailed reference manual, containing far more than most people will ever want to know (I have only glanced at it myself). This could, perhaps, have been printed as a separate book: not only are some people likely to want just the reference manual or just the tutorial and administration guide, but bundling them together makes for an awkwardly thick volume. (O'Reilly also publish a pocket-sized Sendmail Desktop Reference, which is basically a summary of and index into the reference manual in Sendmail.)

This second edition of Sendmail covers version 8.8, but most of it (and certainly the tutorial sections) won't date that rapidly. If you actually administer sendmail then it is an obvious O'Reilly title to add to your collection, but it may also interest curious users — after all, almost everyone uses sendmail, even if indirectly.

Note: there is now a 3rd (2002) edition of Sendmail.

July 1998

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