In article <3677d101-3874-b8e4-87b3-37e4dd870325@tnetconsulting.net> you write:
Normal lists put their own bounce address in the envelope so they can handle the bounces, so their own SPF applies.
Yep. V.E.R.P. is a very powerful thing. (B.A.T.V. is an interesting alternative, but I never messed with it.)
VERP helps identify the bouncing party, but list bounce handling works fine without it. What matters is that it's the list's address in the envelope, not the message author. BATV works OK (I should know, I invented it) but it has its false positives.
I'm saying that I've heard arguments over the last 15 years from people that (FC)rDNS and SPF (independently) are things that will break some portion of email.
Broken rDNS is just broken, since there's approximately no reason ever to send from a host that doesn't know its own name. Broken SPF may or may not be an issue since there are lots of legit ways to send mail that SPF can't describe. R's, John
P.S. I'm strongly of the opinion that if a MLM alters the message in ANY capacity, that it is actually generating a new message. Thus the MLM is the new author. It's just using content strongly based on emails that came into it. - But that's a different discussion that lasted days on the mailman mailing list.
It's an interesting theological argument but it makes little practical difference.