[Mailman-Developers] Camera-ready option to mitigate DMARC issues

[Stephen J. Turnbull]

Alessandro Vesely writes:

 > The idea is to add a footer only in case it is not present,

Aside from the technical difficulties that Mark describes, this
suffers from a really big defect: for this to be actually useful,
you'd need near-100% participation (Authenticated Received Chain has
the same problem).  Once you've got that, no new Mailman code is
needed: just don't use a footer in the first place!  And it requires
effort on the part of providers we already know are irresponsible and
inconsiderate because they provide personal mail services disrupted by
"p=reject", or on the part of users at those sites, many of whom blame
mailing lists, not their irresponsible and/or inexpert providers, for
difficulties with posting.

If you don't get near 100%, then you need to provide the workarounds
for all users and originating sites that don't participate anyway, to
all of your subscribers -- and "nonparticipants" will include the
posters who are most likely to blame the lists for any delivery
problems, and get upset about "different treatment" (eg, From-
munging).