Sblam! – advanced anti-spam filter for web forms

Sblam! is a transparent server-side anti-spam filter for HTTP web forms (blog comments, forums, guestbooks, etc.)

The project includes:

• Bayesian filtering for text and links.
• DNSBL clients for http:BL, SURBL, DroneBL, SORBS, abuse.ch BLs, all using custom asynchronous DNS client based on PEAR Net_DNS.
• Throttling of requests (implemented using APC),
• Automatic blacklist that handles dynamic IPs pretty well,
• Miscellaneous other "plug-ins" that check content and HTTP headers of spammy posts.

The filter maintained at sblam.com has filtered over 10 million posts with accuracy above 99.8%.

See Sblam! homepage (in English).

Sblam! is written in PHP5 and takes advantage of MySQL-specific features (requires MySQL5+ with InnoDB).