[Linux-aus] PSA: Messages sent through LA mailing lists being classified as SPAM

Russell Coker russell at coker.com.au
Fri Jan 15 01:53:39 AEDT 2016

On Fri, 15 Jan 2016 01:04:20 AM Joel W. Shea wrote:
> On Thu, Jan 14, 2016 at 11:50:51PM +1100, Russell Coker wrote:
> > On Thu, 14 Jan 2016 11:05:27 PM Joel W. Shea wrote:
> > > Alternatively, make Mailman reject the message with a DMARC failure
> > > report, and hope that the sender signs with "c=relaxed/simple" to allow
> > > whitespace variation in the header in future.
> > 
> > I don't think that there is any feature of Mailman to do this and I don't
> > think it would be desirable to do so.  But making mailman not munge the
> > headers would be a good feature to have.
> I guess I really meant letting the receiving domain(s) enforcing the
> DMARC policy send the report. But I agree, it would be far better if
> Mailman didn't fold the whitespace in the first place.

DMARC messages are sent to the sysadmin of the sending domain.  I expect that 
few if any mail servers try to send DMARC messages to the originating user, 
and I doubt that would be a good feature to have.

So if someone runs their own personal domain and uses DMARC they would get 
messages about it.  But someone who signs up to Yahoo mail (or any other 
commercial mail service that uses DMARC) will just have mail mysteriously not 
be received.

I think that if Linux mailing lists are to be welcoming to new users then it 
should be possible for them to send mail from Yahoo and have Gmail users 
receive it.  Currently this is not the case, mail from Yahoo sent to this list 
will fail DMARC and be rejected by Gmail.

Yahoo appears to be using p=reject in some of their DMARC entries, they have 
it on yahoo.com but not on yahoo.com.au.  If someone using a yahoo.com address 
suddenly started sending a lot of messages to this list would it cause all 
Gmail users to be unsubscribed?

On Fri, 15 Jan 2016 01:29:49 AM Joel W. Shea wrote:
> On Fri, Jan 15, 2016 at 12:13:51AM +1100, Russell Coker wrote:
> > On Thu, 14 Jan 2016 09:09:59 PM Joel W. Shea wrote:
> > 
> > [...] dmarc_moderation_action means that you will have 2 styles of
> > message being sent out and enough of them will be modified that people
> > who's MUAs can't thread such messages will have almost every thread
> > broken.
> I'm not sure how that would be an issue, since the MUA would be creating
> threads from one or more of the following fields;
> ``Subject'', ``In-Reply-To'' and ``References''

I don't know.  Erik was complaining about it on the LUV list as mutt 
apparently isn't doing what he wants.

> So it shouldn't matter if you've munged the ``From´´ field.

Shouldn't matter, but it can especially when MUAs don't work the way you might 

> > > Do you still need to re-write the From: header just to sign a
> > > message?
> > 
> > No.  But if you want to have DMARC pass then you have to do it.
> Sure, but there was no mention of LA publishing a DMARC policy.

If someone sends mail from a domain that has a DMARC policy I believe that 
there's no other way of making it pass DMARC and DKIM checks.

> > [...] The fact that you advocate for dmarc_moderation_action indicates
> > that you don't really believe in sticking to that RFC issue.
> I've also advocated rejecting the message, or accepting, thus allowing
> the receiver to quarantine/reject the message, and would be my personal
> preference.
> However, you're right that I'd much rather see dmarc_moderation, than
> from_as_list; because I really don't appreciate my "From:" field being
> unnecessarily rewritten, especially if it causes my own Reply-To field
> to be clobbered.

Are you going to stop using gmail.com?  The dmarc_moderation setting seems to 
affect all mail with DKIM signatures and that means gmail.com.

My Main Blog         http://etbe.coker.com.au/
My Documents Blog    http://doc.coker.com.au/

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