John Hinton wrote: > > I don't think my users would be too happy with greylisting, unless it > was done only on blocklist, as they have come to enjoy the immediate > delivery of email. Also, greylisting has the potential of > hurting other > ISPs, clogging their systems, just because they signed up a > few 'stupid > users' who got the latest virus/trojan. If you think back to > some of the > more successful viruses, mailservers everywhere suffered with many > choking and going down. Adding to their mail queues isn't so nice. While I have had a couple of mailservers that were sending legitimate mail complain about this (greylisting all mail), the vast majority have had no problem with it. I use the postgrey script (has it's own yum repo too :) and after a 5 minute delay the first time a triplet (client/sender/recipient) is seen it is auto-whitelisted. And the greylisting happens after all sanity checks and rbls. Vastly reduced spam from spambots which tend to just blast the mail out with no concern for the response. But I only have 200+ mailboxes and around 15-20k emails a day, so YMMV. I think the bottom line is that you have to pick your MTA/Content filter and then get on the mailing list and pay attention. It's an on-going war and there is no set-it and forget-it. alex