Martijn de Munnik:
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> On Thu, 2009-10-22 at 13:03 +0200, Martijn de Munnik wrote:
> > On Thu, 2009-10-22 at 06:35 -0400, Wietse Venema wrote:
> > > Martijn de Munnik:
> > > > Hi List,
> > > >
> > > > Some of our customers use our mailservers as antispam/antivirus gateway.
> > > > So our server accepts mail, does some spam and virus checking and
> > > > delivers the mail to a remote server. Of course I don't want to accept
> > > > mail for non existing users so our mailserver verifies the recipient. So
> > > > far so good.
> > > > But when a spam run is started and our server receive over 100 messages
> > > > per minute the final server wouldn't handle the verifies anymore and is
> > > > responding:
> > > >
> > > > [ID 197553 mail.info] NOQUEUE: reject: RCPT from
> > > > smtp.zonder.com[64.244.96.100]: 450 4.1.1 <rerer...@example.com>:
> > > > Recipient address rejected: unverified address: host
> > > > xxx.xxx.xxx.xxx[xxx.xxx.xxx.xxx] refused to talk to me: 421 too many
> > > > connections; from=<> to=<rerer...@example.com> proto=ESMTP
> > >
> > > To make fewer connections to the downstream machine, see:
> > >
> > > http://www.postfix.org/master.5.html
> > > http://www.postfix.org/postconf.5.html#transport_destination_concurrency_limit
> >
> > These parameters limit the number of simultaneous address verify
> > connections? But my master.cf already has:
> >
> > verify unix - - n - 1 verify
Perhaps surprisingly, Postfix uses the SMTP client for making
connections to your down-stream SMTP server.
Wietse
