[Mailman-Developers] Reply-To: handling
J C Lawrence
Fri, 19 Oct 2001 16:04:22 -0700
On Fri, 19 Oct 2001 15:32:44 -0700
Chuq Von Rospach <firstname.lastname@example.org> wrote:
> On 10/19/01 3:21 PM, "J C Lawrence" <email@example.com> wrote:
>> Note: This does expose an abuse vector:
>> I don't like Bubba.
>> I send a troll to a busy list with Reply-To set to Bubba.
> Aka the "set your followup to /dev/null" on usenet hack.
> I'm of the opinion, and I don't expect to be in the majority, that
> "reply-to" should not transport through a mail list. Either the
> mail list replaces it with a list-centric one, or it deletes it.
There are three base reasons people set Reply-To:
1) They're rewriting their From: header.
2) They're attempting to move a thread to another forum.
3) They're attempting to kill CC'ed posts to themselves by setting
Reply-To to the list they're posting to.
I've already addressed the (fourth) abuse vector. Taking the three
#1 is not fundamentally affected by the change except that they
now starg getting CC's. For reasons not dissimilar to Chuq's I
don't have much sympathy for this.
#2 Will work, partially. With reply-to replacement replies would
never see the other forum. With reply-to extension they'll see
both the other forum and the list list.
#3 Won't change at all as they'll get dupe collapsed
> The real answer are aliases attached to a subscripiton)
Agreed. Different problem tho.
> My argument is that when I send mail to the list, the list
> processes it and then sends out a new message that my message is
> the basis of it.
The debate then is how much influence a poster should have over the
disposition of such a message. Specifically, given that a poster to
a non-reply-to list can entirely control the disposition via
reply-to, how should those abilities be curtailed for a reply-to
By doing reply-to extension we're changing practice as follows:
-- Posters can _add_ to a posts disposition list via Reply-To.
This is different from non-reply-to lists where posters can
entirely replace and define disposition via reply-to.
-- Posters can attempt to move threads to a different forum.
Essentially they can create crossposted threads via reply-to.
Unlike non-reply-to setting lists they can't make a thread leave a
list, they can only add another disposition. Unlike reply-to
replacement, you _CAN_ now have a crossposted thread.
-- Under reply-to extension the original poster who sets reply-to
has the ability to expose an additional address to all subsequent
thread posts. This can be abused, but can also be a Very Good
Thing as it allows, for instance, a non-list-member to track and
aprticipate in a specific thread. Under reply-to replacement
you'd have to be a member of the list to follow the thread (thus
all the requests of, "Please CC me I'm not on the list").
> At that point, the original reply-to is no longer valid, it's what
> the list software says should happen that matters. As the
> bubba-hack shows, to NOT do this opens up lists to abuse in
> not-necessarily-obvious ways, and worse, you leave things in
> ambiguous states, depending on factors most users don't
> understand. Lists act differently based on whether it reply-to
> coerces and whether the original poster coerces reply-to...
This centers on the old debate:
Is a list message an entirely new message or is it a
continuation/version of the message which was sent to the list?
I tend to the latter version.
Yes, the Bubba hack extends an abuse which exists for non reply-to
munging lists to reply-to munging lists.
> ... and you have the issue of which coerced reply-to 'wins'.
Given RFC conformant MUAs this isn't a problem -- they all win.
Here it appears that Pine might not be conformant. MH and NMH are
just fine. JRA is testing out Mutt. I assume someone with access
to Outlook will check that (I don't have access).
> How is the typical user to understand how this all works together,
> and why when they reply to a list, this happens, except when it's
> fred's message?
The arbitrary user is not affected. He replies exactly as per
normal and, as far as his perception is concerned, it Just Works.
J C Lawrence
---------(*) Satan, oscillate my metallic sonatas.
firstname.lastname@example.org He lived as a devil, eh?
http://www.kanga.nu/~claw/ Evil is a name of a foeman, as I live.