[NTLUG:Discuss] [ms.g@noitacude.com: [sb1116] ALERT: Texas "super DMCA" movingthrough the legislature]

[Darin W. Smith]

On Fri, 23 May 2003 08:30:05 -0400, Rob Apodaca <rob.apodaca at attbi.com> 
wrote:

> Changing gears - What I'd like to know is even if an ISP explicitly says 
> you
> cannot do nat nor connect more than one PC without paying for each 
> additional
> PC, how would they know if you were doing it? I really don't know very 
> much
> about packets and what exactly is done to them when they go through 
> nat...can
> an ISP detect if there are multiple PC's behind a nat or even if packets 
> are
> being nat'd? Even if they could, I think you could mask that by simply 
> putting
> two nat routers in series and then placing multiple PC's behind the 
> second
> router.
>

It has recently come to light that someone has developed a method for 
counting the number of machines you have behind a NAT.  Basically, NAT 
works by using another piece of information, like port numbers, to encode 
the packets that go to a particular machine.

Whether you have one NAT or a hundred in series, that encoding is still 
going to have to be there for one of them, and would just get forwarded 
unchanged on the next.  So no, that wouldn't hide you any better.

-- 
D!
Darin W. Smith
AIM: JediGrover