DMARC/DKIM mitigation on maling lists

[Greg Troxel]

Markus Neteler <neteler at osgeo.org> writes:

> On Wed, Nov 8, 2023 at 12:23 PM Sandro Santilli <strk at kbt.io> wrote:
>>
>> Given the enthusiasm, I did this myself.
>> The SAC mailing list is now officially the second mailing list testing
>> the new settings.
>
> For the record:
> I don't like at all that there is no more the [SAC] suffix in the Subject.

I think it's important that we don't discuss "subject tag is missing"
disconnected from "From: line has been set to an incorrect value".  It
is in general (given that we allow people to join lists from domains
that have DMARC policies!) one or the other.

With a modified subject, some senders are going to get rewritten and
then From: won't match per-sender filters in MUAs and more importantly
the "reply" MUA risks sending to the list.  It's this consequence which
has to be weighed against not having subject tags.

(FWIW, I believe that if DKIM had been well established when mailman was
being written, the subject tag feature would not have been introduced or
at least not become normal.)