The mailman fix is worse than the disease. I think the .INVALID fix is
much better, because Reply-all will still work.
From the latest DMARC draft, section 8:
"If the RFC5322.From domain does not exist in the DNS, Mail Receivers
SHOULD direct the receiving SMTP server to reject the message."
As far as I can tell, that bit of poor advice hasn't been implemented.
So if a receiver that is implementing DMARC is faithful to the draft,
that won't work very well (nobody has gotten a TLD allocation for
.invalid, I hope?)
See RFC 2606.
R's,
John
PS: I did a few experiments, and putting two addresses on the From:
line works remarkably well to avoid inappropriate policy failures,
e.g.
From: Marissa <marissam(_at_)yahoo(_dot_)com>, foo-list(_at_)ietf(_dot_)org
Subject: whatever
...