Mail Avenger is a highly-configurable,
MTA-independent SMTP server. It lets users run messages through filters like ClamAV and SpamAssassin during SMTP transactions, so the server can reject unwanted email before assuming responsibility for its delivery. Other unique features include TCP SYN fingerprint and network
route recording, SPF (sender policy framework) as a general policy language, qmail-style delivery of extension addresses, validation of sender addresses through SMTP callbacks, mail-bomb protection, integration with kernel firewalls, and more.
License: GNU General Public License (GPL)
Changes:
Support for newer BerkeleyDB versions, two new configuration options (LogTag and IdentTimeout), and a MSGID environment variable that can be used to correlate rcpt commands with message bodies.
