[Mailman-Users] Gmail and DMARC

[Jim Popovitch]

On Sat, Apr 26, 2014 at 2:24 AM, Stephen J. Turnbull <stephen at xemacs.org> wrote:
> Jim Popovitch writes:
>
>  > TBH, I'm not sure what else there is to look for. :-)  GMail, every so
>  > often, is telling my Mailman that it needs to Auth in order to reflect
>  > From:gmail to other gmail customers.  It's like DMARC without
>  > following the DMARC standard (GMail has a p=none policy).
>
> Is it possible that those users are using their GMail address from a
> non-Google host?  That would explain the intermittent nature of the
> challenge -- it doesn't have the GMail DKIM signature that identifies
> GMail-from-GMail messages.  And it would also explain why it "looks
> like" DMARC, since DKIM is one of the underlying protocols used to
> implement DMARC.

I strip any existing inbound sigs.  The GMail senders were using GMail
web interface.

This looks more and more like a lazy DNS issue, as the MX for GMail
has flip-flopped over the past ~24 hours.  I honestly think that GMail
rotated in a wrong server...the only other possibility is that
powerdns cached a record beyond it's TTL.

-Jim P.