I'm running Mail Security for Exchange on Exchange 2010 and have turned on greylisting, which has helped a lot.
However, I'm trying to see if I can "speed up" the greylisting process for legitimate e-mail.
I'm constantly watching the greylist tab via ERAC, and have a whitelist policy I push out via ERAC that I update whenever I notice greylisting has caught a client, but it doesn't seem to matter to the greylist engine. We have a few clients whose provider uses the hostedmail.com e-mail service, specifically, their e-mails keeps coming from "smtprelay.b.hostedmail.com" which has multiple IP addresses.
The problem I run into is the initial e-mail comes from that host via one particular IP address, gets rejected (as per greylist design), but the 2nd attempt to resend the mail comes back via a whole new IP address, starting the greylisting process over again!
Is it possible to tell EMSX to allow email from that host no matter the IP, or do I really need to track down all the IP addresses associated with that host, so that the greylist engine won't hold up legit emails any longer then needed?