I am curious to know if anyone has any experience with grey-listing as an anti-spam technique. ht
To be a bit more specific, how well does grey-listing work, and has it caused any unexpected problems? (sorry accidently hit cr before I was finished with the last post)
Here is some information on the topic..
milter-greylist home page
Greylisting: The Next Step in the Spam Control War
Exim/Qmail Greylisting Code Download
doesn't answer all your questions but it might prove useful to others who want to reply and need a refresher on the subject.