It's more popular among large providers than small ones.
...
To me, that makes decisions about damage-mitigation work for a
non-essential protocol complicated because one way to eliminate
the damage is to not support the protocol at all, possibly
including stripping its headers whenever they are encountered.
Having talked at length with people at the large providers that use DMARC,
I am sure that there is no possibility that it will go away and it is
likely that more rather than fewer providers will start publishing
restrictive policies.
They understand that it causes problems, and I believe they are open to
implementing changes to alleviate those problems.
Regards,
John Levine, johnl@xxxxxxxxx, Taughannock Networks, Trumansburg NY
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