X-Grey
Greylisting that's Fast

Acknowledgements

I would like to thank Pick Internet and HarmonyLogic for funding the development of this program and for alpha testing. I would also like to thank Gladesoft for feedback and keeping me honest in coding the program and for running a beta test version of this program.

And now, on with the show …

X-Grey is a standalone daemon that implements a greylisting policy that any MTA can use. Currently in production use at Pick Internet, it has cut the spam volume by 90% (on those domains that are currently employing its use).

Features of X-Grey include: