mail.python.org not listening on IPv6

[JulienPalard]

mail.python.org do have an IPv6 (and an IPv4):

$ dig A +short mail.python.org
188.166.95.178
$ dig AAAA +short mail.python.org
2a03:b0c0:2:d0::71:1

But it does not accept emails on its IPv6 interface:

$ netcat -4 mail.python.org 25
220-mail.python.org ESMTP Postfix

$ netcat -6 mail.python.org 25

[ewdurbin]

by default all firewall rules are applied to ipv4 and ipv6 addresses, so this is a postfix configuration issue apparently (since its not even listening on :::25.

it may have a reason as I recall as well, given the hosting platform (DigitalOcean) doesn't allow mail infra on ipv6 to prevent spam. last time I recall contacting them it was basically because of the large number of addresses they allocate per node leading to a proliferation of spammers using their infra.

I'll contact postmasters to see if they recall disabling ipv6 for postfix.