On 12/3/2015 9:02 AM, Marko Cupać wrote: > Hi, > > I have the following in main.cf: > > soft_bounce = no > unknown_address_reject_code = 550 > > Still, postfix server rejects mail from our exchange server with 450 > instead of 550: > > Dec 3 15:41:32 mx2 postfix/smtpd[40509]: NOQUEUE: reject: RCPT from > exchange.senderdomain.org[D.D.D.D]: 450 4.1.2 <some...@recipientdomain.org>: > Recipient address rejected: Domain not found; from=<some...@senderdomain.org> > to=<some...@recipientdomain.org> proto=ESMTP helo=<exchange.senderdomain.org> >
The DNS lookup of the recipient domain failed with a temporary error. Postfix will always defer mail when that happens. -- Noel Jones
