[Mailman-Users] Mailman & DMARC question

[Jim Popovitch]

On Mon, 2018-11-05 at 10:07 -0600, David Gibbs wrote:
> My quandary is: Is there any risk in implementing my own more
> restrictive DMARC policy?
> 
> Currently my DMARC policy is 'p=none' ... but I'd like to change that
> to 'p=quarantine'.
> 
> Is there any risk running mailing lists from a domain with that DMARC
> policy?
> 
> My theory is that there isn't ... since DMARC is mainly concerned with
> the from address and, as long as mail sent from my domain aligns with
> the DMARC policy, everything should be good.
> 
> Is this correct ... or am I missing something?

You are correct, as long as the SPF and DKIM align you can set a
restrictive DMARC policy.  In addition to your p=none, you should add
ruf= and rua= stanzas so that you can see today what impact your present
DMARC settings have.

DMARC on your list domain will also help with any delivery issues for
list notifications, as well as any DMARC wrapped posts.

Further, you can test your setup by creating a test list, and then
subscribing and sending a list email to any of these:

  check-auth at verifier.port25.com 
  autoreply at dmarctest.org
  autorespond+dkim at dk.elandsys.com
  check at dmarcanalyzer.com
  checkmyauth at auth.returnpath.net

-Jim P.