** Mark Goodge <mark@???> [2015-08-27 09:30]:
> On 27/08/2015 09:09, Mike Cardwell wrote:
> >I haven't seen issues either, but then I also use DKIM and SPF. The big
> >one for GMail is making sure you have FCRDNS set up. That is an absolute
> >requirement of delivering mail to a Google mailserver over IPv6.
>
> This.
>
> Not all the domains which go through my mail server have SPF and/or DKIM.
> But the server has reverse DNS on both its IPv4 and IPv6 addresses. I've
> never seen any issues sending to Google's mail servers.
** end quote [Mark Goodge]
Likewise.
I first had IPv6 on my mail server quite some time ago, and then noticed that a
couple of emails to NTL didn't seem to arrive or bounce back. After some
investigation I found that it was down to the fact that Google had introduced
strict checking on IPv6 (taking the opportunity to try to reduce spam). This
took a while to twig though as every time I sent a test mail to my own Gmail
account it got through, presumably because of the fact that it knew about my
non-Google email addresses.
Once I knew what was going on it was simply a case of setting up my reverse DNS
zone for the IPv6 blocks I had and adding SPF records in my forward DNS zones
(I've got both proper SPF and TXT versions to be on the safe side). I could
have done DKIM, but SPF looked simpler. I'll probably look into DKIM at some
point as well.
With this setup I have no problems sending to domains hosted by Google, and I
think it is easier than configuring Exim to use IPv4 for some domains as it
should ensure that other organisations that do the same are covered without any
further modifications.
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