Am 17.05.2014 18:13, schrieb [email protected]: > I routinely see 'pulses' of the following traffic, from myriad IPs > around the planet, hitting my mailservers' postfix front-ends:
typical noise > May 15 09:02:12 mx postfix/smtpd[26321]: NOQUEUE: reject: RCPT from > unknown[69.198.138.134]: 554 5.7.1 <[email protected]>: Recipient > address rejected: 554 5.7.1 Service unavailable; > from=<[email protected]> to=<[email protected]> proto=ESMTP > helo=<iGateway> rejected pre-queue, fine > Iiuc, postfix caches some IP, DNS, etc data to keep performance > efficient in such cases, but I do NOT understand enough about it to know > if these 'pulses' of ~10 connections per 1-2 seconds represent a load on > the system that's unreasonable, and should be further limited. there is not much to limit in the case above you can set "reject_non_fqdn_helo_hostname" before the RBL in your restrictions which needs also change "smtpd_helo_required " to yes to be effective keep in mind restrictions are always processed in their order and so you should have the cheapest one at the begin
