[Mailman-Users] Customize "From" when munging it for DMARC?

[Jordan Brown]

On 8/4/2017 12:51 PM, Mark Sapiro wrote:
> I'm aware of issues with Microsoft services adding 'spoofing' warnings
> to messages where the From: address and the To: address are the same.
> Is this what you were referring to by "Setting it to the list name
> interacts badly with outloook.com and hotmail.com replies." in your
> OP. If not that, then what?

I haven't investigated deeply, but with an original message like:

    Return-Path: <list1-bounces at listdomain.org>
    Return-path: <list1-bounces at listdomain.org>
    Date: Wed, 2 Aug 2017 19:44:35 +0000 (UTC)
    To: list2 <list2 at listdomain.org>, 
    	list1 <list1 at listdomain.org>
    Subject: [list1] ...
    X-BeenThere: list1 at listdomain.org
    X-Mailman-Version: 2.1.23
    Precedence: list
    List-Id: "list1" <list1.listdomain.org>
    List-Unsubscribe: <http://listdomain.org/mailman/options/list1_listdomain.org>, 
    	<mailto:list1-request at listdomain.org?subject=unsubscribe>
    List-Post: <mailto:list1 at listdomain.org>
    List-Help: <mailto:list1-request at listdomain.org?subject=help>
    List-Subscribe: <http://listdomain.org/mailman/listinfo/list1_listdomain.org>,
    	<mailto:list1-request at listdomain.org?subject=subscribe>
    From: Jane User via list1 <list1 at listdomain.org>
    Reply-To: Jane User <jane at example.net>
    Errors-To: list1-bounces at listdomain.org
    Sender: "list1" <list1-bounces at listdomain.org>

Two of my users (on outlook.com and hotmail.com) ended up with
reply-to-all results that were addressed to Joe User and list2, but not
to list1 at all.  (Note that this reply came to me via list2.)

    Return-Path: <list2-bounces at listdomain.org>
    Return-path: <list2-bounces at listdomain.org>
    To: Troop 92 list2 <list2 at listdomain.org>, Jane User
    	<jane at example.com>
    Date: Wed, 2 Aug 2017 20:27:29 +0000
    Subject: Re: [list2] [list1] ...
    X-BeenThere: list2 at listdomain.org
    X-Mailman-Version: 2.1.23
    Precedence: list
    List-Id: list2 <list2.listdomain.org>
    List-Unsubscribe: <http://listdomain.org/mailman/options/list2_listdomain.org>, 
    	<mailto:list2-request at listdomain.org?subject=unsubscribe>
    List-Post: <mailto:list2 at listdomain.org>
    List-Help: <mailto:list2-request at listdomain.org?subject=help>
    List-Subscribe: <http://listdomain.org/mailman/listinfo/list2_listdomain.org>, 
    	<mailto:list2-request at listdomain.org?subject=subscribe>
    From: Susan MsUser via list2 <list2 at listdomain.org>
    Reply-To: Susan MsUser <susan at hotmail.com>
    Errors-To: list2-bounces at listdomain.org
    Sender: "list2" <list2-bounces at listdomain.org>

My theory is that MS is (wrongly) dropping the "To" copy of list1 from
the reply because it's the From, and then (correctly) using the Reply-To
instead of the From.