Fernando Gozalo:
> Hi,
>
> > Fernando Gozalo:
> >> Hi,
> >>
> >> does the postfix smtp client implement the IPv6 to IPv4 fallback
> >> mechanism as browsers do?
> >
> > Postfix implements the MX fallback strategy as defined in the SMTP
> > RFC (5321). In addition, Postfix implements this:
> >
> > 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.
> >
> > Wietse
>
> It works with 1 mx with A and AAAA records.
>
> It didn't work with 2 mx with both A and AAAA records
> (https://bugzilla.redhat.com/show_bug.cgi?id=813863).
What is your smtp_address_preference setting?
Some Idiot Linux distros turn on IPv6 by default, and break Postfix
when a destination has more than two primary MX IP addresses.
For this reason I have changed the default smtp_address_preference
setting. I suggest changing your smtp_address_preference setting,
or upgrading to a newer Postfix that works around Idiot Linux
distros.
Wietse
