On Fri, Apr 26, 2013 at 01:39:19PM +0800, Feel Zhou wrote: > Apr 25 10:02:24 shcx postfix/smtpd[21741]: NOQUEUE: reject: RCPT from > mail.example.com[d.d.d.d]: 450 4.1.2 <some...@example.com>: Recipient > address rejected: Domain not found; from=<some...@example.com> to=< > someb...@sino-progress.com> proto=ESMTP helo=<mail.example.com> > > dig sino-progress.com mx > sino-progress.com. 40 IN MX 10 > qiye163mx01.mxmail.netease.com. > sino-progress.com. 40 IN MX 50 > qiye163mx02.mxmail.netease.com.
> This domain already exist, why noqueue Always with a new thread: http://www.postfix.org/DEBUG_README.html#mail Best guess given scant information: http://www.postfix.org/postconf.5.html#reject_unknown_recipient_domain ... The response is always 450 in case of a temporary DNS error. ... Best practice for most sites: Don't use reject_unknown_recipient_domain. Note for this restriction to pass not only do the MX records have to resolve, but the MX hosts have to resolve to network addresses. Any of this can tempfail. -- Viktor.