Hello,
Well greyfix is designed exclusively for Postfix 2.1 or later, It will not work with other mailers.
It's low and tunable resource usage and high efficiency, the program is written in c and uses Berkeley DB to track mailers,
no additional database server is required to use it.
postfix-policyd, postfix-gld uses Mysql back-end, sqlgrey the fork of postgrey uses SQL databases.
So with Berkeley DB, greyfix eliminates the overhead of SQL and interprocess communication.
By itself it allocates memory only for a single request and the Berkeley DB library can be configured to use very few RAM.
also, it integrates with Postfix's master daemon.
Postfix will shutdown greyfix when it is not used completely freeing its runtime resources.
No administrative burden. Everything happens "automatically".
--
Ali MEZGANI
Network Engineering/Security
http://securfox.blogspot.com/