[exim] Greylisting howto

Hi,

I'm running Exim 4 with OpenProtect

I want to add greylisting.

Currently I have about 200 users / 1500 messages a day.

I read the archives, and I'm very confused/worried/unsure of myself.

Is there an easy to install greylisting system with automated 'whitelisting"
updating of Yahoo and the likes?

Is there a "How To" for Exim & greylisting?

Thanks

Nico