Re: Natted packets

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On 01/09/07 05:58, Lucas Diaz wrote:
My question is if some other router somewhere else on the net (inside my lan) has NATed the traffic?
And the original NATed IP?
This router NATing traffic and my router are in the same network...

Ok, you are wanting to see if there is an additional NATing router somewhere in your LAN?

(I'll presume yes for the rest of this post)

There are some ways that you can attempt to find IP addresses with specific types of behavior (all beyond me) that can be indicative of NATed IPs. I believe that (some of) these tests are based on the TCP sequence number. More specifically, an IP stack *usually* behaves in a predictable way. Thus you can look at the TCP sequence numbers of packets coming from an IP address to see patterns of ranges / sliding windows of TCP sequence numbers. If there are multiple (fuzzy) definable groups, there is a good chance that each group is a given computer. However, this can possibly be hidden by the NATing device.

Much beyond that and I don't know any more. However, I do know that there is a lot of discussion about this on the reverse side on the net. Namely I have stumbled across a lot of discussion where people were trying to use NATing technology on providers that did not want them to, i.e. they charged per device, and what they did to hide them selves from the provider.



Grant. . . .


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