[Mailman-Users] cause of bounces

[Grant Taylor]

I didn't completely follow all of your message.  I think we may have 
been talking past each other.

On 10/17/2017 06:56 PM, Mark Sapiro wrote:
> There's no such thing as a group's address unless the addresses are
> listed along with the group name.

Um....  My interpretation of 6854 § 1 and § 4 makes me think that an 
empty group list is perfectly acceptable.  Further, the group list can 
be non-empty and contain the lists posting address.

> Anyway, using a group name alone as From: avoids DMARC as there is no
> From: address domain for a DMARC lookup.

Agreed.

I would rather do something like the following so that users could reply 
to the message.  (It would also avoid potential MUA issues as indicated 
by RFC 6854.)

I would think that it would be acceptable to use a From "group address" 
that is the mailing list.  I.e.

    From: Mailman Users:mailman-users at python.org;

Possibly even something like the following:

    From:  Grant via Mailman Users:mailman-users at python.org;

Arguably, this is conceptually very similar to what has become the 
defacto method to deal with DMARC today by munging the From:

    From:  Grant via Mailman Users <mailman-users at python.org>

The difference is that RFC 6854 codifies that there are times to alter 
the from.  -  At least that's how I'm interpreting this.

Further, if you believe the fact that the outbound message is indeed a 
completely new message (as I do) then it's completely legit to set the 
from to what ever you want.  ():-)

> That type of forwarding is exactly what is done by Mailman's DMARC Wrap
> Message action and that is the reason that action exists. Because in
> that case the list message is RFC 5322 compliant. However many MUAs,
> particularly mobile apps, have difficulty rendering such a message in a
> good way, so Wrap Message isn't always the best option.
It sounds like you're talking about message/rfc822 message attachments. 
-  That is a viable option.

However I see no reason that you can't take the body copy from the 
incoming email and use it directly in the new outgoing email.  No need 
to message/rfc822 wrap (or other digest like raping) the outgoing message.



-- 
Grant. . . .
unix || die