Policyd is an anti-spam plugin for Postfix (written in C) that does
Greylisting, Sender-(envelope, SASL or host / ip)-based throttling
(on messages and/or volume per defined time unit), Recipient rate
limiting, Spamtrap monitoring / blacklisting, HELO auto blacklisting
and HELO randomization preventation.
Maintained by: Nishant Limbachia
Keywords: greylisting,postfix,antispam,policy server
(the SlackBuild does not include the source)