I've been following this discussion for a while. Graylisting is the main
reason why I got into Exim. I have generally been skeptical of anti-
spam solutions, but it's good to hear from both sides.
I have only e-mailed one person who was using graylisting. I had never
e-mailed him before, and he got the message in about ten minutes.
There is a lot of debate on the graylisting list about the time delay to
use. It seems as though most graylisting users have made their delay
less than 15 minutes. I also set up graylisting to remember a "triplet"
for 100 days.
The three main reasons for the spam problem are that spam is cheap,
easy, and profittable. Graylisting makes spamming more expensive
and more difficult.
I'm still setting up our graylisting server, but am looking forward to see
how it will work. The "inventor" of graylisting is a Sendmail guy, but
others have made it work on Exim.
http://www.digitaleveryware.com/projects/greylisting/
Chris
