> On 2016-11-02 13:27, Wietse Venema wrote: > > Karel: >>> On 2016-11-02 11:36, Wietse Venema wrote: >>>> NOQUEUE: reject: RCPT from unknown[x.x.x.x]: 450 4.7.1 Client host >>>> rejected: cannot find your hostname, [x.x.x.x] >>> >>> Note that this is a 450 status, because the name server did not reply. >>> A proper SMTP client will therefore try to deliver the email later. >> >> but looking in my logs, I see also 450 status when nameserver is >> reachable, but hostname could not be resolved (because it does not exist) > > Please show actual concrete evidence, instead of spreading rumors. > > Wietse >
Here are 8 lines from mail.log The last two lines were logged when the nameservers were down. I have substituted my actual domain with mydomain.com $ grep reject mail.log 2016-10-29 20:57:55 postfix/smtpd[2310]: NOQUEUE: reject: RCPT from unknown[107.179.40.46]: 450 4.7.1 Client host rejected: cannot find your hostname, [107.179.40.46]; from=<x...@ore.net> to=<eax...@yahoo.com> proto=ESMTP helo=<192.168.0.120> 2016-10-30 03:37:23 postfix/smtpd[2390]: NOQUEUE: reject: RCPT from unknown[203.171.31.60]: 450 4.7.1 Client host rejected: cannot find your hostname, [203.171.31.60]; from=<x...@ore.net> to=<eax...@yahoo.com> proto=ESMTP helo=<192.168.0.120> 2016-10-31 05:44:43 postfix/smtpd[2662]: NOQUEUE: reject: RCPT from unknown[198.16.62.240]: 450 4.7.1 Client host rejected: cannot find your hostname, [198.16.62.240]; from=<542...@allen.ra4d.com> to=<ka...@mydomain.com> proto=ESMTP helo=<allen.ra4d.com> 2016-10-31 14:38:48 postfix/smtpd[2957]: NOQUEUE: reject: RCPT from unknown[195.11.232.179]: 450 4.7.1 Client host rejected: cannot find your hostname, [195.11.232.179]; from=<sa...@mydomain.com> to=<check212...@gmail.com> proto=ESMTP helo=<sxlatnqgbs> 2016-10-31 21:34:09 postfix/smtpd[3223]: NOQUEUE: reject: RCPT from unknown[119.128.172.108]: 450 4.7.1 Client host rejected: cannot find your hostname, [119.128.172.108]; from=<vb...@mydomain.com> to=<xiaon...@vip.163.com> proto=ESMTP helo=<XL-20160621FCVQ> 2016-11-01 01:16:31 postfix/smtpd[3315]: NOQUEUE: reject: RCPT from unknown[195.22.126.7]: 450 4.7.1 Client host rejected: cannot find your hostname, [195.22.126.7]; from=<mxilhd...@outlook.com> to=<ipajlcyxl...@gmail.com> proto=ESMTP helo=<niohmihjdm> 2016-11-01 23:49:51 postfix/smtpd[3417]: NOQUEUE: reject: RCPT from unknown[36.230.253.81]: 450 4.7.1 Client host rejected: cannot find your hostname, [36.230.253.81]; from=<z200...@yahoo.com.tw> to=<uakh.f...@msa.hinet.net> proto=SMTP helo=<185.16.172.124> 2016-11-02 07:59:32 postfix/smtpd[3452]: NOQUEUE: reject: RCPT from unknown[62.2.245.123]: 450 4.7.1 Client host rejected: cannot find your hostname, [62.2.245.123]; from=<e-ass...@assura.ch> to=<ka...@mydomain.com> proto=ESMTP helo=<mail.figeas.ch>
