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
