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Postfix Problem with IPv6 settings

Postfix Problem with IPv6 settings


When trying to send email to a gmail account through postfix you can see an error like this in the postfix logs “/var/log/maillog”:

Oct 17 09:47:07 localhost postfix/smtp[4352]: connect to aspmx2.googlemail.com[2a00:1450:4008:c01::1a]:25: Network is unreachable

Oct 17 09:47:07 localhost postfix/smtp[4353]: 6FC6ABFECD: to=<email@example.com>, relay=none, delay=122398, delays=122396/0.03/1.8/0, dsn=4.4.1, status=deferred (connect to alt1.aspmx.l.google.com[2a00:1450:4008:c01::1a]:25: Network is unreachable)

A common cause is because of wrong IPv6 settings. Correct your IPv6 settings and try again. If it doesn’t work post your particular solution here!
If you want to use IPv4 instead, then you should edit the Postfix configuration file:
$ vi /etc/postfix/main.cf
And change “inet_protocols = all” to “inet_protocols = ipv4”, and restart or reload Postfix:
$ /etc/init.d/postfix reload
and flush the Postfix queue:
$ postfix -f

or just wait and mail will start to send.

reference: http://www.solver.io/wp/2012/10/15/postfix-gmail-network-is-unreachable/

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