The UDP Win Chat is a freeware for windows which can be function as a P2P chat on UDP protocol.
This program allwos you to chat with your friends without using any external server. You can set The IP host of the detination PC, set the port to Connect, set text to the destination and more.. and all over the UDP protocol.
Open the program. Set the IP of the destination host. Set the port of the connection. From now the program will connect to the destination host over the UDP protocol.