The Reg does 240/4

Fri Feb 16 20:03:07 UTC 2024

It appears that Mike Hammett <nanog at ics-il.net> said:
>-=-=-=-=-=-
>
>" Does any IPv6 enabled ISP provide PTR records for mail servers?" 
>
>
>I think people will conflate doing so at ISP-scale and doing so at residential hobbiyst scale (and everything in between). One would
>expect differences in outcomes of attempting PTR records in DIA vs. broadband. 

Most consumer ISPs block port 25 so rDNS would be the least of your problems trying to run a home mail server.

>"How does Google handle mail from an IPv6 server?" 
>
>A few people have posted that it works for them, but unless it has changed recently, per conversations on the mailop mailing list,
>Google does not treat IPv6 and IPv4 mail the same and that causes non-null issues. 

As has been widely reported, Google has recently tightened up authentication requirements so
v4 and v6 are now pretty similar.

They won't accept v6 mail that isn't authenticated with SPF or DKIM
but honestly, if you can't figure out how to publish an SPF record you
shouldn't try to run a mail server.

R's,
John