Mail Avenger is a highly-configurable, MTA-independent SMTP server daemon. It lets users run messages through filters like ClamAV and SpamAssassin during SMTP transactions, so the server can reject mail before assuming responsibility for its delivery. Other unique features include TCP SYN fingerprint and network route recording, verification of sender addresses through SMTP callbacks, SPF (sender policy framework) as a general policy language, qmail-style control over both SMTP-level behavior and local delivery of extension addresses, mail-bomb protection, integration with kernel firewalls, and more.

• Why you should use Mail Avenger
• Download
• Installation instructions
• Tips and Tricks for Mail Avenger users
• Recent changes
• Blocking Unwanted Mail with Mail Avenger
  (good overview of Mail Avenger's motivation and approach)
• Slides from talk at 2004 spam conference

On-line documentation:

• aliascheck(1) man page
• avenger(1) man page
• dbutil(1) man page
• deliver(1) man page
• dotlock(1) man page
• edinplace(1) man page
• escape(1) man page
• macutil(1) man page
• mailexec(1) man page
• match(1) man page
• smtpdcheck(1) man page
• synos(1) man page
• asmtpd.conf(5) man page
• asmtpd(8) man page
• avenger.local(8) man page

Useful external links:

• Subscribe to release announcements at freshmeat
• SPF configuration wizard
• SPF specification

Contact:

Please email questions, comments, testimonials, and bug reports to the author (preferably with the words "mail avenger" in the email subject).

Mail Avenger is brought to you by David Mazières of the Stanford Secure Computer Systems group.

Logo credit: Lori Bode, Squink Industries.