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? > > Wietse >
