DMARC -> CERT?

Mon Apr 14 17:29:42 UTC 2014

On Mon, Apr 14, 2014 at 1:03 PM,  <Valdis.Kletnieks at 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 at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004