PTR reverse look up failing

Posted June 13, 2014 5.1k views
Hi On June 12th sometime seems to have stopped reporting PTR records for my domains causing emails to not be delivered. Mail acceptance has been working fine since the beginning for two drops & and now is being rejected Any pointers as to why? thanks on digitaldrop from mail.log ((works))) Jun 11 02:05:07 azonde postfix/pickup[3370]: AEE68120C0B: uid=0 from= Jun 11 02:05:07 azonde postfix/cleanup[3446]: AEE68120C0B: message-id=<> Jun 11 02:05:07 azonde postfix/qmgr[802]: AEE68120C0B: from=, size=4689, nrcpt=1 (queue active) Jun 11 02:05:11 azonde postfix/smtp[3449]: AEE68120C0B: to=, orig_to=,[]:25, delay=3.4, delays=0.04/0.01/2.7/0.67, dsn=2.0.0, status=sent (250 2.0.0 s5B957se000793 Message accepted for delivery) Jun 11 02:05:11 azonde postfix/qmgr[802]: AEE68120C0B: removed ((stopped working)) Jun 12 02:05:09 azonde postfix/smtp[4041]: 0BF8F120EA2: to=, orig_to=,[]:25, delay=2.3, delays=0.03/0/2.3/0.04, dsn=4.3.3, status=deferred (host[] said: 451 4.3.3 does not have matching forward and reverse dns (FAIL) [orthrus:DNS0] (in reply to RCPT TO command)) reports: ptr: ptr No ptr Records exist smtp diag blacklist port scan subnet tool Reported by on 6/13/2014 at 12:43:33 AM (UTC -5), just for you. (History) Transcrip

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2 answers
In the DigitalOcean Control Panel, make sure that the hostname you've assigned to your droplet is a fully qualified domain name (FQDN). So, if your mailserver identifies itself as, then you would want to make sure the name of the droplet is Until you do this rDNS is not going to be possible.

@ asb
Does this also mean that in my OS I also need to set the hostname to actually be the FQDN instead of just the hostname?