Rapid spam filtering system
Provides mechanisms for walking through any arbitrary PHP variable
PHP Email address validator
Fast Bayesian spam filter along lines suggested by Paul Graham
Anti-Spam SMTP Proxy Server implements multiple spam filters
SMTP email proxy and relay server
Anti Spam SMTP Gateway
Per user/admin filtering of individual/group emails
Remote anti spam utility
Python API for Sendmail Milters.
RBL script for server checking
An easy-to-use anti-spam email gateway
Open source DMARC implementation
mapSoN is a challenge/response spam filter for Unix
Secure mail + Tor gateway
Protects you from spam mails and virus mails effectively with milter
Outgoing email rate limiter