Hello Postfix Group, When attempting to send an email to a particular domain,lowlypalace.io, postfix only gets the ipv6 address and does not fall back to the ipv4 address. For example;
status=deferred (connect to aspmx2.googlemail.com[2607:f8b0:4001:c08::1a]:25: Network is unreachable) There is no second attempt for the ipv4 address, although it is resolvable from the mail server; ping alt2.aspmx.l.google.com PING alt2.aspmx.l.google.com (173.194.219.26) 56(84) bytes of data. 64 bytes from ya-in-f26.1e100.net (173.194.219.26): icmp_req=1 ttl=39 time=65.7 ms 64 bytes from ya-in-f26.1e100.net (173.194.219.26): icmp_req=2 ttl=39 time=65.7 ms <snip> Interestingly, I see gmail addresses working when the ipv6 ip is not reachable; Nov 14 11:24:33 mail postfix/qmgr[2760]: 144DB21408CA: from=<u...@domain.com>, size=151283, nrcpt=1 (queue active) Nov 14 11:24:33 mail postfix/smtp[2587]: connect to gmail-smtp-in.l.google.com[2607:f8b0:400e:c02::1a]:25: Network is unreachable Nov 14 11:24:34 mail postfix/smtp[2587]: 144DB21408CA: to=<u...@gmail.com>, relay=gmail-smtp-in.l.google.com[74.125.199.27]:25, delay=1.4, delays=0.04/0.06/0.59/0.72, dsn=2.0.0, status=sent (250 2.0.0 OK 1479151474 z63si23334266pff.293 - gsmtp) <snip> Is there anything I need to change in postfix to help resolve this? Thank you, James