ipv6 PTR record; was: Re: Fwd: Bounce action notification

Ewoud Kohl van Wijngaarden ewoud+ovirt at kohlvanwijngaarden.nl
Mon Jan 20 12:14:55 UTC 2014

On Sat, Jan 18, 2014 at 01:39:14PM +0100, Dave Neary wrote:
> On 01/15/2014 09:38 PM, Karsten Wade wrote:
> > I'm the one with the Linode access, but I'm unclear what/if I can
> > do anything?
> Ewoud can help you out - we need to add a PTR record for the IPv6
> address of linode01.ovirt.org to the DNS so that reverse DNS resolves
> correctly.
> The issue is that gmail and other email providers check whether the MX
> (in this case, linode01.ovirt.org) has a valid IPv6 DNS entry, and
> score you down if you don't.

Actually this is a valid case we haven't mentioned. There is no forward
DNS either. That means we should also create that.

The alternative is to disable IPv6 for the time being. Since
smtp_address_preference[1] is 2.8+ and we run 2.6.6, we can only use
inet_protocols[2]. Currently we don't listen on the outgoing IPv6 anyway
so I don't think this has any negative impact. If there's no objections,
I'm proposing we change inet_protocols from all to ipv4 this evening.

[1]: http://www.postfix.org/postconf.5.html#smtp_address_preference
[2]: http://www.postfix.org/postconf.5.html#inet_protocols

When we've added the forward and reverse DNS, we can enable it again and
properly support IPv6.

> > Also, I'd much prefer that we finish the task of moving off the
> > Linode host. When is that happening?
> Are there plans to move the management of the DNS zone off Linode also?

Reverse DNS is tied to your IP space and since we don't have PI-space,
Linode owns the IP we use. That means when we move away from linode, the
reverse DNS management of that IP becomes irrelevant.

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