On Mon, Apr 14, 2014 at 1:03 PM, <Valdis.Kletnieks@vt.edu> wrote:
The problem is when Yahoo users post to lists that use DMARC, and the result is the yahoo user's mail getting bounced or dumped on the postmaster.
Basically, this is just like old ORBS. If you were an ISP, you had to check your local users' IP addresses smarthosting through your mail server against ORBS or your mail server would inevitably be listed. Now, as then, the solution is: if the domain has a DMARC listing, mail addresses using it aren't permitted to post to the list. As I tried to say before but was probably too subtle -- just flunk validation for all DMARC-using messages, across the board without exception, and then act on that failure as the DMARC DNS records indicate that the sender wants you to. Especially the ones to abuse@ and your other POCs. That'll clean up the use of DMARC right quick. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004