The Anti-Spam SMTP Proxy (ASSP) Server project is an open source platform-independent SMTP Proxy server which implements whitelists and Bayesian filtering to rid the planet of the blight of unsolicited email (UCE). UCE must be stopped at the SMTP server. Anti-spam tools must be adaptive to new spam and customized for each site's mail patterns. This free, easy-to-use tool works with any mail transport and achieves these goals requiring no operator intervention after the initial setup phase.
ASSP is the best Anti-Spam solution and few features are
- Unique Backscatter Detection and Blocking
- Native SSL-support. ASSP will be "Man in the Middle" and will do TLS/SSL-connections even if your MTA didn't support it!
- Resending of blocked eMail to th original recipients by clicking a link from the new eMail Block reports or from the maillog tail
- Improved HELO handling
- Individual weighting of different DNSBL lists
- Weighting of Regular Expression
- Improved community Griplist (GreyIP List)
- Improved performance and memory usage
- Additional to ClamAV you can now use your file-system virus scanner for scanning your eMails
- Lots of more useful tweaks and setting