Sendmail administration is a complex and sometimes daunting task. To manage sendmail, dedicated professional administrators must work on configuration files written in a language with syntactic rules. This book is not an introduction to sendmail, but rather a recipe for addressing the various issues that administrators are often confronted with. The book’s overall philosophy is to define the problem, present a solution, discuss the solution in detail, and then offer references to other problems in the book.

The first chapter is an overall introduction to sendmail, including getting the sendmail software, and compiling it for specific features that are not part of the standard configuration. Many basic functions of sendmail, like delivery, forwarding, relaying, and masquerading, are discussed in chapters 2 through 4. Routing mail via mailertable is discussed in chapter 5. An entire chapter is devoted to spamming; a few years ago, this chapter would have been absent from a book of this kind. Various problems caused by, and solutions to, this growing menace are discussed, including using access database and the domain name system (DNS) blackhole list service, and filtering mail with procmail.

Chapter 7 addresses authentication using the AUTH protocol (RFC 2554). It supports strong authentication techniques, by offering a comprehensive introduction to the topic, followed by a discussion of various problems and solutions. Chapter 8 also covers authentication and encryption, using the transport layer security (TLS) protocol, and using STARTTLS extensions based on RFC 2487. It provides an in-depth discussion of authentication and encryption issues, for example, building a private certificate authority, and certificate-related problems. However, it is not clear on which occasions one would use the solutions presented in chapters 7 and 8; both chapters address similar high-level issues, and each presents different solutions, using different approaches. Security is an important part of sendmail. Though this is discussed in several places in the book, the last chapter is dedicated to a discussion of security issues. Frequently, many Internet security problems are blamed on sendmail, and the author provides solutions to many common sendmail configuration missteps.

Overall, this book will be a blessing for sendmail system administrators, its target audience.