[Mailman-Users] Emails from yahoo members, are getting rejected by yahoo, "Service Unavailable".

[Mark Sapiro]

On 04/13/2014 03:03 PM, Jim Popovitch wrote:
> 
> DMARC checks alignment of *both* DKIM and SPF, if either is broken DMARC fails.
> 
>> SPF does not check the "From:" header line, and that's where the
>> troubles begin with DMARC.
> 
> SPF checks sending IPs (of which your IPs won't match Yahoo's, thus
> breaking DMARC)
> 
> Either an SPF failure or a DKIM failure will cause a DMARC rejection
> if p=reject.


I'm not sure that's correct. I've been testing this so many ways, I'm
not sure what I'm seeing, but I think a reject requires BOTH DKIM and
SPF to be absent or fail. If either passes, no DMARC reject occurs.

There are weird issues though. It seems I can't post from my gmail
address to my yahoo group. I get a non-delivery notice from gmail. I'm
not sure why. The yahoo group exists and my gmail address is a member
with posting privileges.

I'll follow up more after dinner break.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan