Re: RES: ReN: IPv6 tranisition issues

> -----Mensagem original-----
> De: Michael R. Cole [mailto:[email protected]]
> Enviada em: terga-feira, 31 de dezembro de 2002 09:20
> Para: [email protected]
> Assunto: Re: ReN: (ngtrans) IPv6 tranisition issues 
> 
> 
> 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.

That's a gross oversimplification that eliminates the actual problem, so
of course it doesn't sound bad when you put it that way.

When a computer has a global address, you open a socket and get a port,
and you can tell anyone anywhere in the world using any communications
medium that they can reach you there.  You can call someone on the
telephone and tell them, "My cool new game server is at port 1982 on
1.2.3.4!" and it works.  You can send the info via snail mail, and it
works.  One friend can tell another friend, and it works.

With NAT, you can't do that, end of story.  The NAT box HIDES
INFORMATION from BOTH ENDS of the conversation, so you can't know what
the people at the other end see your address and port number to be.

It also does not allow YOU to hide information for protocols it expects
to affect.  You can't do FTP over IPSec, because then the NAT box can't
reach into the FTP packets and modify them.

I would have thought that all of this was pretty well understood by
now...

		--Rod