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

[Jim Popovitch]

On Sun, Apr 13, 2014 at 4:01 PM, Richard Damon <Richard at damon-family.org> wrote:
> If you list modifies the message, in particularly either the subject
> line or body, then the signature won't match and the message is supposed
> to not be delivered.

It's worse than just modification of the message/headers.  DMARC works
off of SPF as well.

-Jim P.