Reliable, flexible, and configurable enough to solve the mail routing needs of any web site, sendmail has withstood the test of time, but has become no less daunting in its complexity. Even the most experienced system administrators have found it challenging to configure and difficult to understand. For help in unraveling its intricacies, sendmail administrators have turned unanimously to one reliable source — the bat book, or sendmail by Bryan Costales and the creator of sendmail, Eric Allman. Now in its third edition, this best-selling reference will help you master the most demanding version of sendmail yet. The new edition of sendmail has been completely revised to cover sendmail 8.12 — a version with more features and fundamental changes than any previous version of the Unix-based email routing program. Because the latest version of sendmail differs so significantly from earlier versions, a massive rewrite of this best-selling reference was called for. The book begins by guiding you through the building and installation of sendmail and its companion programs, such as vacation and makemap. These additional programs are pivotal to sendmail's daily operation. Next, you'll cover the day-to-day administration of sendmail. This section includes two entirely new chapters, "Performance Tuning" to help you make mail delivery as efficient as possible, and "Handling Spam" to deal with sendmail's rich anti-spam features. The next section of the book tackles the sendmail configuration file and debugging. And finally, the book wraps up with five appendices that provide more detail about sendmail than you may ever need. Altogether, versions 8.10 through 8.12 include dozens of new features, options, and macros, and this greatly expanded edition thoroughly addresses each, and provides and advance look at sendmail version 8.13 (expected to be released in 2003). With sendmail, Third Edition in hand, you will be able to configure this challenging but necessary utility for whatever needs your system requires. This much anticipated revision is essential reading for sendmail administrators.