Re: Time Warner cable

["Dan Ritter-2" <user=13@nabble.blu.org>]

 On Fri, Oct 26, 2007 at 10:24:27AM -0400, Boland, John wrote: 
> how can nat be detected? 
> would you have to inspect the packet contents? 
> 

http://www.cs.columbia.edu/~smb/papers/fnat.pdf

(Look at the OS-dependent characteristic TTL; this detects 
routers, rather than NAT, and can be disguised by a firewall 
that arbitrarily resets TTL.) 

(Look at grouping of IP sequence numbers. Count the number of 
groups. Now you have a probably lower bound on the number of 
hosts active behind the NAT. This can be defeated by the BSDs, 
which use randomized sequences, and Solaris, which uses a 
separate sequence for each connection.) 



-dsr- 

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