Message Sniffer is a multi-platform, open source, spam-filtering tool for ISPs, educational institutions, and corporate IT departments. Messages are scanned through your e-mail server with an advanced pattern-matching engine that identifies unwanted content, message sourcing, and obfuscation techniques. The program is a simple, flexible command line utility that works very much like a virus scanner and can be integrated with many e-mail server software products. Advanced "cellular peer-server" and "folded token matrix" technology makes content filtering practical even on modest hardware - typically scanning messages in under 300ms. Live performance statistics are available on our web site. The rule base is updated several times per day to capture the newest spam and can be customized to fit your specific needs.

Version 2-3 adds the ability to run in persistent-server mode for improved performance.