** Sometime around 21:19 +0100 11/30/01, Thomas Gramstad sent everyone:
>* J C Lawrence
>  > On Fri, 30 Nov 2001 Omar Thameen wrote:
>  >> If you have the capability, is there any reason not to place the
>  >> subscriber email address in the To: header of list messages...
>
>  >> I can't see that much is lost when mailing list information can be
>  >> placed in other headers, such as those recommended by RFC2369
>  >> (List-Help, List-Post, etc.).
>
>  > Unfortunately many MUAs still don't support RFC 2369.
>
>RFC 2919 recommends List-Id:.

What I'm about to say is, I'm sure, exactly the point that Thomas was 
making; I just want to add some more color to the distinction between 
RFCs 2369 and 2919, particularly since not all of our members are up 
to date on their RFCs.

To wit: List-ID: has a slightly different purpose than 
List-Subscribe, List-Post, etc.; specifically, List-ID: is intended 
to be a persistent and unique identifier for the mailing list. 
List-ID: should (ideally) never change, even if the domain in which 
the list resides changes; in contrast, most of the RFC2369 headers 
will tend to change if the list's domain changes (or if a different 
MLM is installed, etc.)

In this sense, List-ID: is (or should be) preferred over the To: 
header as an invariant method of identifying a mailing list. For this 
reason, we have deployed List-ID: across all of our mailing lists. 
RFC2919 is merely a starting point, but I think it's a pretty good 
one.

Meanwhile, RFC2369 headers remain a handy way to communicate specific 
(and potentially changeable) list information to subscribers.

If the goal is to uniquely identify a mailing list to the 
subscribers, I agree that List-ID: is a good start. However, for 
those brane-ded MUAs that cannot filter on headers other than To:, 
From:, etc., List-ID: (alone) will not be useful; a quasi-invariant 
"standard header" would have to be used.


__________________________________________________________________________
Vince Sabio                                                  [EMAIL PROTECTED]

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