----- Original Message -----
From: "Stephen J. Turnbull" stephen@xemacs.org To: "Franck Martin" franck@peachymango.org Cc: "Mailman Developers" Mailman-Developers@python.org Sent: Monday, July 8, 2013 2:01:43 AM Subject: Re: [Mailman-Developers] Adding DMARC support for Mailman 3
Franck Martin writes:
If the From: contains the posting email of the mailing list, one would think that the default becomes reply to the list, but this is where Reply-To: can be used.
Most users do not display Reply-To; many cannot (at least not at their level of technical skill). This means that they get no indication of the author of a message unless the author signs the body of the mail, which often isn't done, and is impossible to enforce. So this setting is simply unacceptable except on announce/advertising lists (where Reply-To is usually set to some other address anyway) and on anonymous lists (which as far as I know are relatively rare).
If this option becomes a popular filter on large mail hosts, discussion lists (ie, the kind of mailing list that Mailman was originally intended to serve) will take a severe, perhaps fatal, blow.
This is speculation, and broad fear of the future...
The current practice for a postmaster is to trust (or not) emails from specific mailing lists, not who post them to the list. Adding DKIM to the list and taking ownership will only improve it.
I hope this helps alleviate concerns.
You should really read the code of the patch for MM2 and try it.