how to use proxy serve in multiplayer game

i need proxy server to connect host and client in different network

1. i start a proxy server with ip xxx:10746

2. i start host server with proxy server enabled, and connect to the proxy server 10746, everything goes well

3. and the host server be given a new port 50110 by the proxy server

4. i start a client without proxy server enabled,

5. client connect the proxy server with port 50110, and then connected to the host, it all works well

6. client player and see host player , host can see client also

7. but they can't see the movement between each other

i have debuged many times

and it seems that when client connect to host, the proxy server can relay the correct message ID: ID_REQUEST_CLIENT_INIT also host can reply a correct msg : ID_CLIENT_INIT by proxy server but when client move, the proxy server relay a message with ID unknown : 0; but relay to right host server address and when server move, the proxy server relay a message with ID unknow : 5; even relay to wrong client address

any one can help me??? thanks a lot

have i missed somewhere?