efa-project.org

Before switching to EFa I used to use postgrey and they have a default list containing big senders with big pools so the chance of getting the same mail client after it has been greylisted is slim so by default greylisting is turned off.

check out their defautl whitelist: http://postgrey.schweikert.ch/pub/
download the tgz and look into postgrey_whitelist_clients

Answered my own question as this is already done in: /etc/sqlgrey/clients_fqdn_whitelist