Re: [Savannah-hackers-public] Fwd: DMARC and gnu.org lists

[Bob Proulx]

Hi Reuben,

Reuben Thomas wrote:
> [Not sure where I should be sending this; Eli suggested here!]

The best place is going to be either address@hidden or to the FSF
sysadmins at address@hidden .  It all depends upon how deep things
need to go.  I see in the forward that you did mail this to
address@hidden but I don't see it in the list there.  Did you perhaps
get a bounce from it there?

Savannah project is mostly unrelated to managing the mailing lists.  A
couple of us (Karl and myself) happen to be on both teams.  I will
forward it to address@hidden with my response.  I am going to set
Mail-Folllowup-To: address@hidden and yourself to encourage mailers
to do the right thing when responding.

> For some years now, the domain from which I'm writing has had a strict
> DMARC configuration. This interacts badly with mailing lists that
> rewrite messages sent out with the From address of the original
> author, as my emails end up self-classifying as junk.

The problem is that DMARC is fundamentally incompatible with mailing
lists.  If you are sending from a strict DMARC policy then you can't
use mailing lists.  This is one of those cases where trying to fix one
problem has created a new problem.

Note that gnu.org Mailman doesn't do anything with DKIM or to DKIM.
Therefore if you are only using DKIM then it will be passed through
verbatim.  This is different from some sites that actively generate
DKIM signatures for the mailing list itself and override the sender's
DKIM.

Supposedly in the future http://arc-spec.org/ is the proposal to fix
all of the previous problems so far.  But that is still a proposal for
the future.  I haven't looked at it myself.  I am always skeptical of
"solutions to all previous problems" when every previous solution has
created a large number of new problems.

> Further, Eli has brought to my attention that these messages can cause
> other subscribers' mail systems to automatically unsubscribe them from
> lists which the recipient system assumes are spamming.

Yes.  The problem is that when your MTA rejects a message this will
create a bounce message back to the mailing list.  Mailing list
management software will see that mail to your address is bouncing.
Mailman keeps a running score.  After too many bounces it will decide
that your email address is not deliverable and will suspend further
delivery attempts to it until it is manually enabled again.

> mailman can be configured to work with strict DMARC; would it be
> possible to do this for all gnu.org lists, or at least bring it to the
> attention of individual list admins, if it must be done list-by-list?

Is there a missing "If" in the start of that sentence?  I think so.
As far as I know the answer is, No.  Using mailing lists is one of the
problems of using a strict DMARC configuration.  Sorry.

> I've not seen problems with lists where I have in the past persuaded
> the admins to make the necessary changes.

What changes are those?  If they are not intrusive then of course we
would be happy to oblige.

Bob

> ---------- Forwarded message ----------
> From: Reuben Thomas <address@hidden>
> Date: 25 August 2017 at 15:01
> Subject: DMARC and gnu.org lists
> To: address@hidden
> Cc: Eli Zaretskii <address@hidden>
> 
> 
> Hi,
> 
> For some years now, the domain from which I'm writing has had a strict
> DMARC configuration. This interacts badly with mailing lists that
> rewrite messages sent out with the From address of the original
> author, as my emails end up self-classifying as junk.
>
> Further, Eli has brought to my attention that these messages can cause
> other subscribers' mail systems to automatically unsubscribe them from
> lists which the recipient system assumes are spamming.
>
> mailman can be configured to work with strict DMARC; would it be
> possible to do this for all gnu.org lists, or at least bring it to the
> attention of individual list admins, if it must be done list-by-list?
> I've not seen problems with lists where I have in the past persuaded
> the admins to make the necessary changes.
>
> thanks,
>
> Reuben
>