On 05/02/2014 10:51 PM, Mark Sapiro wrote:
On 05/02/2014 05:21 PM, Andrew Partan wrote:
Is there some way of ignoring the DMCAC bounces? That way a message From: some...@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.)
Yahoo, ATT, MSN, Hotmail, and Google all seem to respond with 5.7.x status codes. If ignoring 5.7.x responses is a good approach, and a large fraction (significant majority, I suspect) of users use services that give 5.7.x responses, and mailman is already able to parse those responses, then it sounds like ignoring 5.7.x bounces (or counting them differently) is a viable step to take.