Dave Crocker writes:
It is worth noting the the list-subscription headers often used now
provide an MUA with a way of detecting that this is list email. Hence
it could at least try to treat reply-to differentially. That would
not be a perfect solution. Reply is still sometimes set by the author
and other times set by the mailing list agent, so there is no way to
be sure what its semantics really are.
FWIW, I implemented that, and found that the following three-part hack
worked tolerably well:
1. Reply-To points to one of the To/Cc addresses.
2. Reply-To is different from From.
3a. EITHER: The Reply-To localpart forms part of the envelope sender
localpart, which also contains a word like owner, return, request etc.
3b. OR: The Reply-To localpart occurs in a List-* field.
I'd _love_ to see something less hackish in mail-ng.
(I also think the interaction between a "reply to all" command and a
"reply-to" field is tricky, for some of the same reasons.)
Arnt