2 ms·how would TCP hole punching even work? TCP has state and a handshake. UDP doesn't.by algesten 6y agohow would TCP hole punching even work? TCP has state and a handshake. UDP doesn't.zozbot234 6y agoUPnP can be used to setup port forwarding if the NAT gateway is configured correctly.algesten 6y agosure. I think it's a bit different though. upnp is like some remote control of your fw.