May 26, 2018
Easy-to-use greylist milter for sendmail and postfix
This is a port of Emmanuel Dreyfus’ milter-greylist.
Grey listing is a wonderful spam filtering technique, which uses a behavior trick spammers never resend a message when they get a temporary error, whereas real MTA do. The idea is to refuse any mail on first attempt, and accept it after some time has elapsed.
milter-greylist is a stand-alone milter written in C that implement grey listing.