On 23.09.2012 21:51, Ralf Hildebrandt wrote: Hello,
>> - try to block as much spam as possible before forwarding (in our case >> that would mean RBL and pre-queue filters, as we are not allowed to drop >> mail we successfully received) > I think you already have some sort of spam filtering in place? Yes, we have Greylisting+RBL+FcrDNS in front, but full Amavis/SA with Bayes is Post-Queue at the moment. It detects (and tags) a lot of spam that got through the first line of defense, but as far as we know we are not allowed to automatically drop anything based on that tagging. Only the user may opt-in to do so. So all those mails have to be forwarded. We are working on migration to Pre-Queue. >> Any other recommendations? Is SRS/PRVS helpful here? > No, since the forwarding server will be blacklisted anyway (since it's > the source). SRS can help nevertheless, since forwarding breaks > SPF. As a benefit it allows you to notice bounces and react accordingly. Okay, I will have a look at SRS. Thanks, Bernhard
