Subject: Re: #1003 USEFOR 3.1.3 Message-ID: Proposed text

From: Harald Tveit Alvestrand <[email-masked]>
Date: Fri, 01 Jul 2005 14:17:37 +0200

--On torsdag, juni 30, 2005 16:21:33 +0000 Charles Lindsey 
<[email-masked]> wrote:

> The only genuine not-globally-unique IP addresses are the ones set aside
> for local use (127.0.0.1 is the best-known). Even IP addresses obtained on
> a DHCP lease are uniquely yours so long as you hold them. Hence
> s/many/some/.

I guess you haven't been in that many NAT discussions....

The 10.0.0.1 set-asides are just one example of addresses that are 
simultaneously in use by multiple machines at multiple times.
Other examples are internal networks using addresses assigned to others 
(yes, they exist) and multihomed hosts.

The fact is - a machine has no way of being sure his IPv4 address is 
"uniquely his" or not.

---

From: "Charles Lindsey" <[email-masked]>
Date: Mon, 4 Jul 2005 13:32:06 GMT

>The fact is - a machine has no way of being sure his IPv4 address is 

If an IP packet sent from Timbuktu using that address arives at your
machine (and only at your machine), then it was "uniquely yours" at that
moment. IOW, which IP addresses are suited for use in <msg-id>s (and
<path-identity>s too for that matter), is ultimately determined by the
routeing tables.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: [email-masked]      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9      Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5

---

From: Graham Drabble <[email-masked]>
Date: Mon, 04 Jul 2005 23:05:43 +0100

On 29 Jun 2005 Harald Tveit Alvestrand <[email-masked]> wrote
in news:[email-masked]: 

> NEW:
> 
>    Some software will try to match the <id-right> of a msg-id in
>    a case-insensitive fashion; some will match it in a case
>    sensitive fashion. Implementations MUST NOT generate two
>    message-IDs where the only difference is the case of characters
>    in the <id-right> part. 

Should we give some guidance on what we would like people to do about 
matching? Given the efficiency of case sensitive comparison maybe 
something like:

Some software will try to match the <id-right> of a msg-id in a case-
insensitive fashion; some will match it in a case sensitive fashion 
(which is to be preferred). Implementations MUST NOT generate two
message-IDs where the only difference is the case of characters
in the <id-right> part.

That would alow a future standard to move to remove the restriction 
on generating MIDs differing just in case.

-- 
Graham Drabble
http://www.drabble.me.uk/