This Nutshell Handbook® is far and away the most comprehensive book ever written on sendmail, the program that acts like a traffic cop in routing and delivering mail on UNIX-based networks. Although sendmail is used on almost every UNIX system, it's one of the last great uncharted territories--and most difficult utilities to learn-- in UNIX system administration.This book provides a complete sendmail tutorial, plus extensive reference material on every aspect of the program. What's more, it's authoritative, having been co-authored by Eric Allman, the developer of sendmail, and Neil Rickert, one of the leading sendmail gurus on the Net.This book covers both IDA sendmail and the latest version (V8) from the University of California, Berkeley. It also covers the standard versions available on most systems, such as those found on Sun and DEC/Ultrix workstations.The book is divided into four parts. Part One is a tutorial on understanding sendmail from the ground up; starting from an empty file, it has the reader work through exercises, building a configuration file and testing the results. Part Two covers practical issues in sendmail administration. Part Three is a comprehensive reference section, while Part Four consists of appendices and a bibliography.