Re: DMARC methods in mailman

Theodore Ts'o <tytso@mit.edu> Tue, 20 December 2016 22:35 UTC

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Date: Tue, 20 Dec 2016 17:35:44 -0500
From: Theodore Ts'o <tytso@mit.edu>
To: John Levine <johnl@taugh.com>
Subject: Re: DMARC methods in mailman
Message-ID: <20161220223544.ktfd2kzrz46mjdnu@thunk.org>
References: <m1cJIF7-0000DEC@stereo.hq.phicoh.net> <20161220195601.23551.qmail@ary.lan>
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On Tue, Dec 20, 2016 at 07:56:01PM -0000, John Levine wrote:
> In article <m1cJIF7-0000DEC@stereo.hq.phicoh.net> you write:
> >Just a random idea, I don't think I have seen it before, but I may have missed
> >it.
> >
> >What about adding a checkbox in the mailman profile for subscribers of the
> >lists that basically says: if you detect that the sender is using DMARC then
> >please rewrite the From header.
> 
> Whether a mail system enforces DMARC policies is up to the system's
> manager, not individual users.  Even in the IETF, I expect that many,
> perhaps a majority, of users have only the dimmest idea what if
> anything their operator does with DMARC.

This starts getting more complicated, but the mailing list could try
intentionally sending a message which fails DMARC (e.g., with a
claimed from address of example@yahoo.com) to the mailing list
subscriber and see if it gets bounced, and use that to set the default
for that setting automatically?

						- Ted