Re: ReN: IPv6 tranisition issues

----- Original Message -----
From: "Keith Moore" <[email protected]>
To: "Michael R. Cole" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, December 31, 2002 12:28 AM
Subject: Re: ReN: (ngtrans) IPv6 tranisition issues


> >  A NAT box is just simply
> > a retooled router,
>
> that's a truly bizarre statement.  I suppose it's true from a
> hardware perspective, but it's like saying that a NAT box is
> just a retooled computer with a couple of network interfaces -
> true, but irrelevant to the question at hand.
>
> > just that some are better and some are worse.
>
> all NATs break applications.  some NATs know about a few more
> protocols than others, but no NAT can handle every possible protocol,
> many protocols simply cannot be made to work transparently through NAT.
>
> Keith
>

Your definition of the word break must be different than the one in the
dictionary. If an application works with a NAT box, then it is NOT BROKEN!
Your claim would also say that a timesharing system with only 1 public IPv4
address would not work which is what a cone NAT mimics. That is, a cone NAT
fools that public Internet into thinking that a LAN or other subnet is in
actuality a single machine. At any rate, a NAT box is a patch that gets
around the problem that a good sized chunk of the IPv4 address space was
wastefully allocated to the original players at essentially zero cost.

Maybe your first experience with a NAT box was with a really crummy one? If
that is your only experience or of you have no experience with NAT boxes,
then you have no business crticizing them. Some NAT software that I have
tried was absolutely horrible.

I am not trying to say that the better NAT boxes will work with ALL
applications. Somehow, the cable companies are able to use them at their
headends without breaking applications. However, I have noticed that
enterprise-class NAT boxes use a server-client setup so that applications
are not really aware or can tell that they are indirectly connected to the
Internet. Symmetric NAT boxes probably do work better in part because they
mimic a timesharing system with one public IPv4 address for each user.

Of course, some applications are very picky about what they will eat.

MIke Cole, [email protected]