The QmailToaster is a full blown mail server distribution for use with most rpm based Linux distributions. The QmailToaster is distributed as source rpm's which require compiling on the host system before installation. This is done to meet licensing requirements set forth by the original creator of Qmail, D. J. Bernstein.
The last official release of Qmail was in 1998, and as such QmailToaster has included many patches to update functionality. In addition it has been integrated with a few other niceties, such as web based e-mail and web based administration.