On Sun, 9 Jul 2017, Wietse Venema wrote:
Unfortunately Google has stopped accepting mail from my server via IPv6
and I haven't been able to figure out why or resolve the problem.
However, it accepts mail via IPv4 just fine. Thus, I would like to
configure Postfix to use IPv4 when sending mail to Google. I can see that
this is posible by destination domain using transport_maps. So, I could
use transport_maps to specify that all mail to @gmail.com would be sent
via IPv4. However, there are many other domains that use Google's email
services. Rather than try to list all of them, I was wondering if instead
it was possible to force IPv4 by destination MX instead. In that case, I
could just specify all of Google's MX's and work around this problem.
Sorry, transport mapping happens before DNS lookup. Maybe you can
fix your IPv6 setup by making sure that the PTR record for your
IPv6 address resolves properly: the address->name lookup should
produce a name that resolves to the IPv6 address. Otherwise you
can expect delivery problems.
Thanks - I have FCrDNS configured already for my IPv6 address (and have
for some time), so that doesn't seem to be the problem.
Scott
