Gmail (thus Nanog) rejecting ipv6 email

Sun Apr 3 01:21:43 UTC 2022

It appears that Michael Thomas <mike at mtcc.com> said:
>> Google at least adds ARC headers in Gmail, and did the editing of RFC8617.
>
>ARC resolves into a previously unsolved problem: reputation. ...

No, actually it doesn't, as has been repeatedly explained.

ARC addreses the problem that mailing lists do a lousy job of spam
filtering, A list that usually sends lovely clean mail sometimes
doesn't, since a typical list forwards anything with a subscriber's
address on the From line including spam from cleverish spammers who
take pairs of from/to addresses from stolen mailboxes.

ARC lets the recipient system look back and do what we might call
retroactive filtering, using info about messages as they arrived at
the previous forwarder. While it would be nice if lists did a better
job of spam filtering, they don't, and ARC is a reasonable remedy for
that.

R's,
John