[Mailman-Users] Executive summary of DMARC issues

[Stephen J. Turnbull]

Barry S. Finkel writes:

 > Is this also true?
 > 
 > Users from DMARC-reject domains send mail to mailing lists, and the
 > resulting mail from the mailing list is rejected.  Enough
 > rejections can cause the mailing list possibly to be blacklisted
 > for sending lots of "spam" mail.

The rejections themselves will be received by the mailing list
(assuming RFC-conforming recipients), so I think this is unlikely in
theory.  I haven't heard of this happening, and Mark says he hasn't
either.

The failure notices received by DMARC senders are another matter.
These are not supposed to be used for blacklisting, but as we already
know, Yahoo! and AOL are desperate.  OTOH, they're already known to be
hostile to mailing lists; getting blacklisted by them is not news.  I
suppose we could worry that they would publish their blacklists to be
used by others, but it was pointed out to me by Murray Kucherawy that
MAPS was shut down by lawsuits, and it seems likely that a public
whitelist or blacklist would attract them too.

My estimate is that this is not something to worry about because it
will be mitigated by any of the options already implemented, and it's
not something to complain about because there's no evidence it
actually happens.  IMO, we need to avoid crying wolf; there are way
too many people (including a number of Mailman list operators) with a
vested interest in painting Yahoo! and AOL as well-intentioned but
overwhelmed by circumstances beyond their control.

Steve