If two hosts
Y are connected to the Internet with NAT.
Both NATs are of cone-restricted type.
Now assume there's a server
Z which stores all translated public addresses of
Y can get each other's translated public IP address from
X wants to talk to
X can't send a message to
Y's public IP because
Y's NAT is cone-restricted.
But if both
Y send a message to each other simultaneously, then their message can reach
Can anyone tell me why this happens??