This complete guide to installing, configuring and using qmail to manage Unix-based mail systems explores how this alternative to sendmail can solve specific mail-handling problems. qmail concentrates on common tasks like moving a sendmail setup to qmail, or setting up a "POP toaster", a system that provides mail service to a large number of users on other computers sending and retrieving mail remotely. The book also fills some crucial gaps in existing documentation, detailing exactly what the core qmailsoftware does, how it routes and queues incoming mail, how it routes mail for local or remote delivery, precisely how it interprets a .qmail file for local delivery, and how it schedules remote deliveries and decides if and when to retry failures. This book is the definitive source readers need for using up-and-coming mail server.