Gmail MX over IPv6

[Bernhard Schmidt]

Am 21.06.2012 08:28, schrieb Mansoor Nathani:

Hello Mansoor,

> Since Gmail has enabled AAAA records for some of its MX hosts, my IPv4
> only machine gets the Gmail IPv6 address and attempts to deliver email.
> Its only when the timeout has been reached will it try the IPv4 address.
> 
> I am curious if anyone else is experiencing this or perhaps I need to do
> something on the CentOS 6 box to disable IPv6 till the time when it has
> native IPv6 capability.

Good time to deploy IPv6 to your MTA :-)

Have a look at http://www.postfix.org/postconf.5.html#inet_protocols and
http://www.postfix.org/postconf.5.html#smtp_address_preference . OTOH,
if you get a timeout your system is broken anyway, since a
well-configured system will return destination unreachable immediately.
You would not notice it. So please show "ip -6 addr; ip -6 route" from
the server.

Best Regards,
Bernhard