>> It uses UDP queries to a small server written in perl, which has >> rather nice performance since the perl server keeps the greylist data >> in an in-memory hash, UDP is pretty cheap, so the server just handles >> the requests as they arrive, no locking needed. It also means that if >> you have a pool of servers they can efficiently share the greylist >> database.
The daemon is at http://www.taugh.com/greydaemon It's intended to be run from daemontools, logs to stdout, can run on 127.0.0.1 for a private setup or a real IP for multiple hosts. It needs to start as root to attach to a low numbered port (1999 by default) but can then drop back to a normal user. It can read a list of IP ranges to whitelist, and saves its state from time to time both so you can see what it's doing and so it doesn't have to start from scratch if you restart it. The plugin is: http://www.taugh.com/daemon_greylist The only parameter is the IP of the daemon. All the parameters like the minimum retry time are in the daemon, not the client. This greylister is less aggressive than some others I've seen, but it does a good job of deterring zombie mail while not needlessly delaying mail from hosts that do retry. R's, John
