This book starts with setting up a qmail server and takes you through virtualization, filtering, and other advanced features like hosting multiple domains, mailing lists, and SSL Encryption. Finally, it discusses the log files and how to make qmail work faster.
Qmail is a secure, reliable, efficient, simple message transfer agent. It is designed for typical Internet-connected UNIX hosts. Qmail is the second most common SMTP server on the Internet, and has by far the fastest growth of any SMTP server. Qmail's straight-paper-path philosophy guarantees that a message, once accepted into the system, will never be lost. Qmail also optionally supports maildir, a new, super-reliable user mailbox format.