Postfix
Postfix is an open source mail transfer agent (MTA), a computer program for the routing and delivery of email, that is intended as a fast, easy to administer and secure alternative to the widely-used Sendmail. Formerly known as VMailer and IBM Secure Mailer, it was originally written by Wietse Venema during a stay at the IBM T. J. Watson Research, and continues to be developed actively until today.Postfix is also the default MTA in Trustix Secure Linux and Mac OS X Panther.
