Media praise for sendmail

"This book must have set the size record for O'Reilly. It is industrial strength coverage for the workhorse agent of the Internet messaging world known as Sendmail. This is the province of system administrators, an invaluable handbook, and a nice companion to companion books TCP/IP Network Administration, DNS and Bind, and MH & xmh. The publisher appropriately enough chose a bat to adorn the bookcover -- for this spooky subject that requires an introductory section entitled 'why is sendmail so complex.' This book is not for your ordinary Internet end user -- but it's a godsend for the people who have to make internetwork messaging systems work -- done by the guys who helped write the code." --Book Review, ISOC News, November 1993

"O'Reilly & Associates had been promising a book on sendmail for so long, I was beginning to think that it would never come out. Just as I was ready to give up on it completely, Sendmail by Bryan Costales, Eric Allman and Neil Rickert, arrived. The book is well worth the wait.

"For years UNIX administrators have been searching frantically for any book that could explain sendmail in plain English, and that is precisely what this book does. It's one of those once-in-a-decade books, a brand-new classic.

"Allman is the author of sendmail itself, but any UNIX administrators who tried to wade through the sendmail manual know his original documentation was as clear as mud. Fortunately, the sendmail book is well-written, and the material is thoughtfully organized.

"The most notable feature of this book is its completeness. The
Unix System Administration Handbook by Nemeth, Snyder and Seabass (Prentic-Hall) touches briefly on sendmail. And another O'Reilly book, TCP/IP Network Administration by Craig Hunt, gives a more complete explanation. But with
sendmail, you finally get some lengthy explanations that shed some real light.

"For example, a full explanation of the M (macro) option for the configuration command appears early in the book. The equates for each of the variables (P, A, F, S, R and so on) are explained in detail so intelligible that even the most complicated (configuration) lines will make a lot more sense. Early in the text, the authors introduce the concept of writing your own file and debugging it as you go.

"Sendmail administration is universally acknowledged as the most difficult in Unixdom, but in spite of its ultratechnical contents, this book is easy to read, and it is interesting too. For example, I was struck by a set of examples showing how the Bourne shell, C shell and the sendmail D (define) command all set a variable of a single letter to a value.

"The most irratiting part of learning sendmail was the
sendmail,cf file and its rule sets. This book demonstrates its excellence by explaining the five critical rule sets for address resolution. In painstaking--but not painful--detail, all the parts of the rules are explained and demonstrated. The book explains in plain English that rule set 0 modifies the address to form the triple, the three basic parts that are needed internally to get the mail to a delivery agent. And the sendmail book shines when it describes in simple language that rule set 3, which sees everything first, separates out the address part, while rule set 0 selects and appends the appropriate mailer. Administrators the world over will applaud the understandable explanation at last.

"As administrators well know, sendmail preforms address translationss that are sometimes difficult to follow. Luckily, the authors do a superb job of explaining how addresses are rewritten with these rules. Using alphabet letters as examples, the authors demonstrate how three rules change x to y, then to
z and finally to a. From here on, diligent readers can readily create their own file, line by line, rule by rule, until they have a workable, debugged configuration file.

"You will find that sendmail is a practical book with practical solutions for real administrators at real compputer sites. A good example of this is the authors' unequivocal endorsement of the use of mail hubs to simplify mail delivery. As administrators well know, having mail scattered on every workstation in the mail domain is an administrative nightmare. But mail channeled through a single point is manageable even in a huge domain. Acknowledging this simple concept, the authors then show how to configure both sendmail and the systems to set up and recognize the mail hub.

"Sendmail would be worth the money if it were just a book on
sendmail, but this book goes the distance, because it is an E-mail book. It discusses the related issues of DNS' relationship with mail, aliases, .forward and the mail queue."

--Bruce Hunter (, Open Systems Today December 1993