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.
These details are provided for information only. No information here is legal advice and should not be used as such.
At one point, Open Hub analyzed source code for this project based on code location(s) available at that time. Since then, the code locations have been removed.