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 > > So it is already limited to 1 connection per ...? I guess I don't > completely understand how this works? >
Or should I also limit the relay transport? http://www.postfix.org/ADDRESS_VERIFICATION_README.html#probe_routing > > > > Wietse > > > > >
