Gmail MX over IPv6

James Cloos cloos at
Thu Jun 21 21:40:58 CEST 2012

>>>>> "MN" == Mansoor Nathani <jkrolan at> writes:

MN> Since Gmail has enabled AAAA records for some of its MX hosts, my IPv4 only
MN> machine gets the Gmail IPv6 address and attempts to deliver email. Its only
MN> when the timeout has been reached will it try the IPv4 address.

Your log shows that you use postfix.

Add this:

smtp_address_preference = ipv4

to to tell postfix to use only ipv4 for outgoing smtp.

The postconf(5) man page explains:

,----< excerpt from postconf(5) >
| smtp_address_preference (default: any)
|        The address type ("ipv6", "ipv4" or "any") that the Postfix SMTP client
|        will  try  first,  when  a destination has IPv6 and IPv4 addresses with
|        equal MX preference. This feature has no effect unless the  inet_proto‐
|        cols  setting enables both IPv4 and IPv6.  With Postfix 2.8 the default
|        is "ipv6".
|        This feature is available in Postfix 2.8 and later.

That doc snippit reminds me that you could instead add:

inet_protocols = ipv4

to do the same thing.

James Cloos <cloos at>         OpenPGP: 1024D/ED7DAEA6

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