[Mailman-Users] Ignore DMARC bounces?

[Mark Sapiro]

On 05/02/2014 05:21 PM, Andrew Partan wrote:
> Is there some way of ignoring the DMCAC bounces?  That way a message
> From: someone at yahoo.com will not not increase the bounce count of
> all Yahoo, AOL, Hotmail, ATT, MSN, and Comcast users.


It's difficult. If The local MTA is refused and reports directly to
Mailman at SMTP time, Mailman will only see the SMTP status, e.g. 554,
521, or 550 in your examples. It is not possible to distinguish DMARC
from other failures just by this 5xx status.

More likely, the local MTA accepted the message from Mailman and is now
delivering a DSN. If every MTA delivered an RFC 3464 compliant DSN with
an RFC 1893 extended status code, one could just ignore 5.7.x bounces,
but even your example services don't all use a 5.7.x code even though
the RFC is clear that that is the code for security or policy rejection.

Then there is the fact that many real world MTAs report in their own way
and don't necessarily provide enough information to tell what the reason
is. Take a look at Mailman/Bouncers/* to get an idea of what you'd be up
against.


> Yahoo & ATT say this:
> 	554 5.7.9 Message not accepted for policy reasons.  See
> 	http://postmaster.yahoo.com/errors/postmaster-28.html
> 
> AOL says this:
> 	521 5.2.1 :  (DMARC) This message failed DMARC Evaluation
> 	and is being refused due to provided DMARC Policy
> 
> Comcast says this:
> 	550 5.2.0 x4fx1n03n5DGQ1A034fysP Message rejected due to
> 	DMARC. Please see
> 	http://postmaster.comcast.net/smtp-error-codes.php#DM000001
> 
> MSN/Hotmail say this:
> 	550 5.7.0 (BAY0-MCn-Fn) Unfortunately, messages from (N.N.N.N)
> 	on behalf of (yahoo.com) could not be delivered due to
> 	domain owner policy restrictions.)


-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan