>But this allows spammers to determine valid accounts.
knowing a valid email address is not sufficient to get past IMGate, is it? > I guess its better >than allowing a zillion message in and having to bounce them. exactly >It would be >cool to somehow automatically block or blacklist an ip after so many 5xx >errors.. That's easy to do by looking at the log files with a script and writing the IPs to an mta_clients_dict.map file. one complication is that if the attack is coming from 100s or 1000s of IPs, the total of rejects per IP will build up slowly and make the threshold trickier to set. and perhaps the bulk of the attack will come from low-volume IPs. >I'm not using postfix as a gateway, maildirs are my final destination :-) > >I just tried using unknown_local_recipient_reject_code = 550 but I'm still >seeing 450s? postconf | grep code shows what? Len
