[Mailman-Developers] Adding DMARC support for Mailman 3

[Franck Martin]

----- Original Message -----

> From: "Murray S. Kucherawy" <superuser at gmail.com>
> To: "Franck Martin" <franck at peachymango.org>
> Cc: "Stephen J. Turnbull" <stephen at xemacs.org>, "Mailman Developers"
> <Mailman-Developers at python.org>
> Sent: Monday, July 8, 2013 6:57:03 AM
> Subject: Re: [Mailman-Developers] Adding DMARC support for Mailman 3

> On Mon, Jul 8, 2013 at 12:26 AM, Franck Martin < franck at peachymango.org >
> wrote:

> > 1) may not be necessary, if mailman recognizes the bounce message as in
> > section
> > http://tools.ietf.org/html/draft-kucherawy-dmarc-base-00#section-15.8
> 
> > eg "550 5.7.1 Email rejected per DMARC policy for example.com "
> 
> > and does not increase the unsubscribe/bounce counter for the receiving
> > email
> > address. I suppose MM3 bounce processing is better than with MM2, so this
> > may be already addressed.
> 
> > Some people have requested this feature, so it is fair to include it,
> > rather
> > than them having to tweak the associated MTA (which some do not have
> > control).
> 

> I don't think the idea of telling people to include or go look for a
> particular substring in the SMTP reply text will ultimately work in a
> standards document, which relegates this logic to the realm of heuristics.
> We've already seen resistance to that effect on the IETF lists. We'd be
> better off trying to register some enhanced status codes and asking the
> community to begin using those.

Mailman 2 read already the substring, and it is common practices amongst ESP to do that to better classify bounces, at least between soft and hard bounces ( http://www.boogietools.com/Products/Windows/BounceStudioEnterprise/Email-Bounce-Categories.asp ) 

I suspect this process has been improved in MM3, but I have not had a look at the code. The purpose is for mailman to recognize 5.7.x bounces and not count them against the recipient (or as soft bounce). Hard bounce is the default for any non recognized bounce. 

Finally, yes, DMARC should register X.7.17 on http://www.iana.org/assignments/smtp-enhanced-status-codes/smtp-enhanced-status-codes.xml