I have been working on mail filtering for the last 6 years and built a number of boxes to act as gateways/relays for clients incoming mail (and even a few outbound mail gateways as well to filter what employees are sending out) and have tried locking-down as many things as possible to decrease spam (as have we all, I know) and it is appearing that SPF is not really taking off like we had all hoped, which is a shame, it is very easy & very good. It looks like Domain Keys has a chance of being very important. I would like to see Zimbra integrate Domain Keys in to a future release. I understand that it is complicated though. Sysadmin's will need to run through a few steps, wihch are not hard, but you do need to read carefully & following instructions well. Finally, you need to publish your key in to your public DNS as a TXT record. It is worthwhile. I hope to see it soon. We really like Zimbra a lot. Thanks all. Peace.
Thanks very much.
Peace. Love. Linux.
*Asterisk Consultant To The Stars *