[Mailman-Users] Which from, reply and DMARC settings for a discussion group?

Stephen J. Turnbull stephen at xemacs.org
Wed Jan 21 03:36:37 CET 2015

John R Levine writes:

[About munging p=reject addresses in From]

 > I've been doing this for the better part of a year, with some very
 > non-technical users on lists for my church and a bunch of folk
 > dancers. For the most part, they don't even notice it.  Perhaps one
 > or two wrote to me to ask what it was.  Do you have concrete
 > experience that says otherwise?

Just reports on this list, and on python-* where somebody
sophisticated mentioned that they didn't appreciate their address
being deprecated as ".invalid" (which is the logical deprecation
according to RFC if you aren't going to provide forwarding).

My users aren't affected by dmarc_moderation_action by their nature
(virtually no Yahoo! or AOL users @xemacs.org, and the Asian
affiliates of Yahoo!, often-seen on my academic lists, are DMARC
"p=none" domains).

 > Remember that their real address is still there, e.g.:
 >    From: Marissa M <marissa at yahoo.com.dmarc.fail>

I'm aware of that; the problems are that (1) some (few? many?) users
have indicated that they dislike it), and (2) providing forwarding
service is outside the scope of Mailman, and probably not available to
the great majority of list owners.

Are "dmarc.fail" subdomains generally available?  If such a service
could be made generally available (theoretically no problem, I
suppose, as the MX for example.com.dmarc.fail could point to
mail.example.com), that would be a great name for it.  But if there is
no general service, such names will proliferate, and your service
(because it's such a great name) will be mimicked (with mail sent to
it presumably to end up rejected?) by third parties who don't
understand the scheme you've implemented.

 > > 3.  Mailman can't implement it anyway, because Mailman not only
 > >     isn't the only MTA on the block, it isn't an MTA at all.
 > It's true, it needs cooperation from whatever MTA receives the
 > rewritten addresses.  The code isn't hard, for people who want to
 > do it.

Code is trivial, except where code is law.  Eg, on hosted cPanel
sites, as alluded to above.


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