Re: What I've been wondering about the DMARC problem

["Murray S. Kucherawy" <superuser@xxxxxxxxx>]

On Thu, Apr 17, 2014 at 6:34 PM, John Levine <johnl@xxxxxxxxx> wrote:

>"If the RFC5322.From domain does not exist in the DNS, Mail Receivers
>SHOULD direct the receiving SMTP server to reject the message."

As far as I can tell, that bit of poor advice hasn't been implemented.

Why is that poor advice?  It's not uncommon for an MTA receiving mail to confirm that the message is replyable, at least insofar as an A and MX are available for whatever comes after the "@".

-MSK
 

PS: I did a few experiments, and putting two addresses on the From:
line works remarkably well to avoid inappropriate policy failures,
e.g.

 From: Marissa <marissam@xxxxxxxxx>, foo-list@xxxxxxxx
 Subject: whatever
 ...

Huh, interesting.  Likely accidental, alas.

-MSK