Routing of Mail List Replies using the "Reply-to" Header

[Keith Marshall]

[In response to an aside comment, appearing in the "AC_FOREACH Public? thread]

On Thursday 20 October 2005 1:31 pm, Stepan Kasal wrote:
> On Thu, Oct 20, 2005 at 11:48:20AM +0100, Keith MARSHALL wrote:
> > Oops.  Forgot that GNU's list mailers don't set the Reply-to header
> > properly, (can this not be fixed?), and only replied privately to
> > Stepan.
>
> this can be easily set in mailman.  Mailman help doesn't recommand it,
> pointing to: http://www.unicom.com/pw/reply-to-harmful.html
> though there is also: http://www.metasystema.net/essays/reply-to.mhtml

Interesting references.  Having read both, I find myself in agreement with 
Simon Hill's view, as expressed in the latter reference, and therefore I must 
respectfully disagree with Chip Rosenthal's view, as expressed in the former,
which would appear to be the basis for the (IMHO misguided) mailman help 
recommendation.

Here's my view on the subject:

1) When you post mail to the list, I receive a copy;  the "To" header 
identifies the list as the destination, while the "From" header tells me it 
originated from you; the "Reply-to" header, if it hasn't be modified, 
requests that I should reply directly to you.

2) If I simply select my mail client's "Reply" option, then I will send a 
reply privately to you, but the other list subscribers will not see that 
reply;  in 99.9% of cases this is not what is wanted -- when replying to list 
mail, all replies should normally be directed to the list, so that all 
subscribers, including you, will see it.

3) Chip Rosenthal suggests that the solution to this is to educate list 
subscribers to always select the mail client's "Reply-to-All" option, when 
replying to list mail.  I *must* respectfully disagree.  This most definitely 
is *not* the solution -- it results in you, and every other subscriber who 
has contributed to the discussion thread receiving *two* copies of my reply. 
You may not mind this, but I can do very well without it, especially when I 
have to download two copies of replies to me, and I am on a 56kB dial-up 
connection.

4) If the "Reply-to" header is set, by the mail list system, to always point 
back to the list address, then the problem of multiple copies doesn't arise;
replies simply go back to the list when the mail client's "Reply" option is 
selected.  This is exactly what is required, in 99.9% of cases.  Chip 
Rosenthal claims that this renders the originator's address unavailable, for 
the 0.1% of cases where a private response is desired.  However, this is a 
false claim -- the appropriate address *is* available in the "From" header, 
so to reply privately, the user has only to reply to the address shown there; 
some mail clients even offer a choice of replying to the "From" address or 
the "Reply-to" address, I believe, (and indeed KMail allows me to make just a 
choice).

> I use mutt, with the config command "subscribe".  I can press "L" to send
> the reply to the list, "r" to send it to the sender and "g" to send it to
> both.

There are, of course, other possible solutions.  It appears that mutt is 
allowing you to choose to reply to address in the "List-post" header.  This 
is a commonly recommended solution to the "Reply-to-List" problem, but 
unfortunately, it is not well supported by popular mail clients -- especially 
those which are prevalent on the Win32 platform.

When I am at home, as I am at present, I don't have any problem replying
solely to the list address -- in KMail, I simply right click on the "To" 
header, where the appropriate address appears, select the "Reply-to" option, 
and the job's done.  When I am at work, however, it is a very different 
story.  Here, I am obliged by Company policy to Win2K as my operating system, 
and Lotus Notes as my mail client.  This gives me only two options: "Reply" 
to the address in the "Reply-to" header, or "Reply-to-All".  If I select 
"Reply", and the mail list system has not set the "Reply-to" header to direct 
replies to the list, then the originator gets a private reply, and the other 
list subscribers never see that response.  OTOH, if I select "Reply-to-All", 
then either I have all manner of rubbish to clear out of the "To" and "Cc" 
fields in the reply form, including the "bounces" address user by the mail 
list system to send to me, or the originator of the message to which I am 
responding gets a private copy of my response, plus an additional cc sent via 
the list.  Furthermore, all other subscribers who have contributed to the 
thread in like manner will also receive the list copy plus an additional 
private copy.

Now, when I respond to mail on the MinGW lists, hosted by SourceForge, and 
with the "Reply-to" headers pointed back at the lists, I have gotten into the 
habit of simply selecting "Reply", to get the action I want -- my reply goes 
only to the list address.  When I do likewise on the autoconf list, or the 
groff list, my reply goes privately to the originator of the message to which 
I am replying, and bypasses the list.

With the above in mind, I would much prefer if "Reply-to" headers were set to 
ensure that the default reply address is that of the respective mailing list.

Regards,
Keith.