Suppose nodes A and B are each behind their own NAT firewall(9.7 Network Address Translation).
A ──── NAT_A ──── Internet ──── NAT_B ──── B
A and B attempt to connect to one another simultaneously, usingTCP. A sends to the public IPv4 address of NAT_B, and vice-versafor B. Assume that neither NAT_A nor NAT_B changes the port numbersin outgoing packets, at least for the packets involved in thisconnection attempt. Show that the connection succeeds. (Note that,because A has already sent a packet to B at the time B’s packet toA arrives at NAT_A, the latter packet is allowed through, and isdelivered to A.)
