Subject: Re: [v6ops] Draft on email transition to IPv6 from IPv4 for sevice providers and other communities

From: Keith Moore <[email-masked]>
Date: Sun, 24 Jul 2011 08:42:22 -0400

If you're rate limiting IPv6 mail at the SMTP level, presumably you're going to reject some IPv6 SMTP connections so that they'll fail over to an MX that only accepts IPv4.  That introduces a delay that isn't under control of the server.  On the other hand, if you limit how often you return MX records that have domains that have AAAA records, that doesn't delay IPv4 mail at all.

Gert Doering <[email-masked]> wrote:

>Hi,
>
>On Sun, Jul 24, 2011 at 02:01:01AM -0400, Keith Moore wrote:
>> I'm not sure what the best way to do this is - maybe have DNS
>> servers randomly return MX records with v6 addresses (or not) with
>> a configurable probability?   Everything else seems like it would
>> have the undesirable side-effect of delaying IPv4 mail traffic.
>
>Please explain why returning a MX records with v6+v4 address will
>delay IPv4 mail traffic.
>
>Gert Doering
>        -- NetMaster
>-- 
>have you enabled IPv6 on something today...?
>
>SpaceNet AG                        Vorstand: Sebastian v. Bomhard
>Joseph-Dollinger-Bogen 14          Aufsichtsratsvors.: A. Grundner-Culemann
>D-80807 Muenchen                   HRB: 136055 (AG Muenchen)
>Tel: +49 (89) 32356-444            USt-IdNr.: DE813185279