In article
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you write:
And yet it is still happening, despite there being a great deal of
discussion in the archives... :/
Yes, because at this point, all of the solutions are worse than the
problem. See this page for a roundup of DMARC mitigations:
http://wiki.asrg.sp.am/wiki/Mitigating_DMARC_damage_to_third_party_mail
The work on ARC is coming along fairly fast. There was a second
compatibility event a couple of weeks ago among various
implementations, and people tell me there should be usable libraries
around the end of the year. Once there's an ARC addon for Mailman and
we use that, the DMARC damage should drop considerably, without us
having to change the way we use our lists.
R's,
John