A simple test for email via IPv6

[Matyas Koszik]

On Tue, 30 Apr 2013, [utf-8] ВаНориК ХОНдатОв wrote:

> Hello again,
> many thanks for discussing the security/abuse problems with autoresponder.
> Will it be a good solution to use sender's SMTP-server for response? Of course, i understand that this can't prevent false responses inside mail domains based on one SMTP server.

You could just give a '550 Yes, your ipv6 works!' error message for every
incoming message. That way you're not sending anything anywere, pushing
the responsbility of generating a bounce back to the sender MTA, which
should already have authenticated the sender properly. This is similar to
your idea, but allows greater flexibility.