<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Aug 22, 2014 at 7:24 AM, Nick Hilliard <span dir="ltr"><<a href="mailto:nick@foobar.org" target="_blank">nick@foobar.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">On 22/08/2014 15:16, Lorenzo Colitti wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Are you following the "Additional guidelines for IPv6" section of<br>
<a href="https://support.google.com/mail/answer/81126" target="_blank">https://support.google.com/<u></u>mail/answer/81126</a> ?<br>
</blockquote>
<br></div>it looks like Google is trying to enforce SPF / DKIM on ipv6 connections where there is no similar requirement for ipv4. Is there a particular reason for this? It's causing a lot of breakage.</blockquote>
<div><br></div><div>I believe the answer has to do with the fact that a lot of IPv6 email is spam and the fact that if you can't/won't do what's suggested in the "additional guidelines for IPv6" then you can always continue to use IPv4. From what I've heard it's somewhat of a consensus position among large email operators on what to do for IPv6 SMTP inbound.</div>
<div><br></div><div>Note that from the text it sounds like SPF / DKIM is not strictly required, but it looks like a PTR record is a hard requirement.</div></div></div></div>