On Thu, Oct 10, 2013 at 02:39:41AM +0200, Dominik George wrote:
> > The correct description is:
> >
> > When both IPv4 and IPv6 support are enabled, the Postfix SMTP
> > client, for Postfix versions prior to 2.8, will attempt to
> > connect via IPv6 before attempting to use IPv4. Starting
> > with 2.8 protocol preference is controlled via the new
> > smtp_address_preference parameter.
>
> That's not the case on two independent systems here. Whether IPv4 or
> IPv6 is used is completely random. This:
"The case" is exactly as described. Random by design. This is the
intended behaviour of
smtp_address_preference = any
with a static preference, Postfix may fail deliver mail to a
reachable destination, just because enough IPv4 or enough IPv6
addresses are dead. Remember, Postfix tries a limited number of
MX addresses per delivery.
--
Viktor.
