[JDEV] NAT Issues

Dan Kegel dank at alumni.caltech.edu
Sun Dec 17 20:38:16 CST 2000


Bernd Eckenfels wrote:
> didnt understand that completly, so let me reiterate:
> 
> Two Peers A, B
> Two Masq Gateways a, b
> A Address Server X
> 
> A sends it's ip address in a UDP Packet to a fixed Port at X
> X will record A's address from inside the data and a's address from
> sender-ip

Nope, X records A's IP and port number from the IP packet it receives,
and a unique id from inside the data.
 
> Now B joins the game, it sends X his IP Address and asks X to notify A
> X sends a packet to A telling it to contact B. ...
> Now B sends a packet to a. It uses which port?

It uses the port that X observed on the packet from A.

> A is notified by X and sends a packet to b. It uses which destination port?

It uses the port that X observed on the packet from B.

This is all explained, if poorly, at
http://www.alumni.caltech.edu/~dank/peer-nat.html

- Dan




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