Preface

Since its release in 1998, qmail has quietly become one of the most widely used applications on the Internet. It's powerful enough to handle mail for systems with millions of users, including Yahoo Mail and VSNL (the largest ISP in India), while being compact enough to work on even the smallest PC Unix and Linux systems. Its component design makes it easy to extend and customize while keeping its key functions secure.

Qmail's design is rather different from its best-known predecessor, sendmail. People who are familiar with sendmail often have trouble recasting their problems and solutions in qmail terms. In this book, I try first to help the reader establish a qmail frame of mind, then show how the pieces of qmail work, and finally show how qmail can deal with some more complex mailing tasks such as handling mail for multiple domains, mailing lists, and gateways to other services.