On 08/22/2014 11:24 AM, Bjoern A. Zeeb wrote:
and frankly your MX should have reverse mapping and that name
(whatever it is) should have some AAAA or A records if you want to do
mail (note the forward -> reverse -> forward does not have to end up
on the same name, e.g., could be IN MX mx42.example.com -> IN AAAA
2001:db8::42 -> someothername.example.net).
I host my email at home, and I got a fixed IPv4 address partly for that
reason.
I got native IPv6 from my ISP a few months ago, but I have been
absolutely unable to get my ISP to delegate IPv6 reverse DNS zone for my
address space to my server.
In fact, in one of the locations where the $work hosts it's servers, we
have native IPv6, with a /64 delegated to our racks, and that provider
is unwilling/unable to delegate the reverse DNS for that address space,
too. The best I could get out of them was "generate the reverse DNS file
for your servers, send by email to so-and-so and he will put it up when
he has the time".
Neither of those machines are sending anything resembling spamn (knock
wood).
So, much as I would LIKE to have reverse IPv6 DNS on my mail servers, in
some cases it is just not possible.
Otherwise you were (are) just a random spambot using one of too many
addresses a day to send mail. And a lot of people have been
implementing a similar policy on IPv4 for years, though this is (was?)
in no RFC at all to my best knowledge. /bz — Bjoern A. Zeeb
