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

[Jim Popovitch]

On Mon, Apr 14, 2014 at 8:55 PM, Keith Bierman <khbkhb at gmail.com> wrote:
> While the process of revising the RFC should have been followed, it does
> seem that they are trying to solve a real problem.

Bingo!  The dmarc folks (many of who are IETF participants) ignored
and performed an end-run around the standards process.

> Mail should come from who it says it comes from, not make it trivial
> to pretend to be someone one isn't.

It is. I am sending you this email via the list.  It contains my
words, and no way conveys the responsibility, nor does it delegate the
ownership, to the list.

> So why not adopt a standard where the *sender* is always the list? The
> obvious downside is that "reply to poster" stops working, but do these
> "security" tools care if the reply-to is different from sender? if the list
> default is "reply to poster" set the reply to as the original sender, but
> "correctly" identify the message as coming from the mail server automation
> ... not the original sender.

Reply-to is more of a client initiated setting.  Mailman works off of
Return-Path, and then there is also a formal RFC defined "Sender"
header.  Dmarc designers choose to ignore these well defined RFC email
headers and, independently of any standards process, choose to focus
solely on the From header.  After all, RFC 5322 is only 8 years old,
not the decades that the dmarc folks would like people to think.

-Jim P.