Valvula
OpenSource high performance mail policy daemon for Postfi
Valvula is a OpenSource high performance mail policy daemon for Postfix, written in ansi C, that provides out of the box support for sender login mismatch, mail quotas, per user and per domain blacklists and whitelists and much more.
It is system administrator friendly by providing many automatic features (like automatically detecting Postfix MySQL databases to be able to detect local domains and local accounts to make better decisions).