end2end? (was: RE: Where NAT disenfranchises the end-user ...)

Fri Sep 7 20:47:05 UTC 2001

On Fri, Sep 07, 2001 at 11:57:24AM -0700, Mike Batchelor wrote:

> Well of course, that was my point. Where do you draw the line? The packet
> as received is not identical to the packet as it was sent, even when NAT
> is not involved. Along the way, various things get modified, the packet
> is encapulated, unwrapped, re-encapsulated, TTLs get decremented, ... all
> things that are necessary and part of the process of getting the packet
> to its destination. NAT just has more necessary things to change. I'm not
> defending NAT, I dislike it as much as the next clueholder, I am just
> taking the devil's advocate position for the sake of discussion.

Encapsulation does not modify the encapsulated packet. It just sends a new
packet that happens to have a data portion which can be interpreted by the
remote end as being a packet which it should forward from there.

TTL decrement A) was intended to be rewritten on a per-packet basis, by
design, and B) is not identity information in any fashion.

Please name one part of a "normal TCP connection" (IE, without anything in
between but, say, some copper wire and ethernet NICs carrying IP directly,
and a router or two doing straight per-hop forwarding) which both gets
rewritten, and has *any* form of identity, or for that matter, wasn't
explicitly intended to be rewritten per-hop by the origional spec.
-- 
***************************************************************************
Joel Baker                           System Administrator - lightbearer.com
lucifer at lightbearer.com              http://www.lightbearer.com/~lucifer