Thank you. Marius.
-----Original Message----- From: owner-postfix-us...@postfix.org [mailto:owner-postfix-us...@postfix.org] On Behalf Of Wietse Venema Sent: Tuesday, August 26, 2014 2:43 PM To: Postfix users Subject: Re: Postscreen - max parallel incoming connections Wietse Venema: > Marius Gologan: > > I'm running a stress test against Postfix, running smtp-source command with > > 1.000 parallel connections from one source IP. > > When postscreen is active, at about 400-460 connections I get "421 4.3.2 All > > server ports are busy". > > Please do not blame the messenger of the bad news. > > POSTSCREEN tries to hand off of connections to SMTPD. You are running > into the condition where all SMTPD ports are busy. > > No amount of POSTSCREEN tweaking will prevent that. Additionally, "421 4.3.2 All screening ports are busy" means that too many clients are waiting for DNSBL/WL lookups, "greet wait" test, or other tests. A client needs to repeat a test when its result has expired. But that is not the problem that you report. Wietse
