Home page logo

nanog logo nanog mailing list archives

Re: end2end? (was: RE: Where NAT disenfranchises the end-user ...)
From: "Joel Baker" <lucifer () lightbearer com>
Date: Fri, 7 Sep 2001 14:47:05 -0600

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 () lightbearer com              http://www.lightbearer.com/~lucifer

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]