The qmail Handbook by Dave Sill
The qmail Handbook is designed to guide system and mail administrators of all skill levels through the installation, configuration, and maintenance of the qmail server. Author Dave Sill, a longtime qmail user, system administrator, and technical support agent (as well as the author of the popular online tutorial "Life with qmail"), provides you with the practical tools to work with this popular mail server.
Sill begins with a discussion of qmails architecture and features, and then delves into a thorough investigation of the installation and configuration processes. You'll learn how to install qmail on several operating systems, and gain valuable insight into proper configuartion, testing procedures, and performance tuning. You'll also learn how to administer users and mail, install filters, and oversee daily qmail operation and maintenance. Throughout, Sill focuses on topics essential to all mail administrators, elaborating on such subjects as configuring mailing list managers, controlling spam, secure networking, scanning for viruses, hosting virtual domains and users, and creating dial-up clients.