slackbuilds_ponce/network/policyd

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.