SMTP over IPv6 : gmail classifying nearly all IPv6 mail as spam since 20140818

[Darren Pilgrim]

On 11/2/2014 12:38 PM, Matija Grabnar wrote:
> On 11/02/2014 06:55 PM, Darren Pilgrim wrote:
>> On 8/22/2014 2:46 AM, Matija Grabnar wrote:
>>> So, much as I would LIKE to have reverse IPv6 DNS on my mail servers, in
>>> some cases it is just not possible.
>>
>> Can you describe those cases?  I can't think of any scenarios where
>> you'd run a correctly-configured public MX and not have reverse DNS.
 >
> Bah - I have a correctly configured public MX on my home network (static
> IPv4, static IPv6). It's correctly configured, but I have been as of now
> unable to convince my provider to delegate reverse DNS (for IPv6) to my
> DNS. They are simply not set up for that. Otherwise, the MX is
> completely correctly configured. Under IPv4 it even has a PTR (for the
> lone static IPv4 address).

Get a small VPS and have it act as MX and smarthost relay.

> And I've had similar problems ("we are not set up to delegate reverse
> DNS for IPV6") with a hosting provider. I had a suggestion on the list
> that I should simply rehost my machines, but alas it is not practical,
> since the provider was chosen for a bunch of other parameters (bandwidth
> cost, hosting cost, etc), with IPv6 connectivity an afterthought.

I've had providers tell me that as well, then add that they can set the 
reverse DNS upon request.  If they can't do either, run away from them 
very fast--they just made it very clear they don't have a good design.