WinSock, how to pass from server to LAN's PC through internet

There is a client LAN_CLIENT who is on LAN (office, university or any other place). There is a HOME_CLIENT connected directly to the internet. Now how HOME_CLIENT can communicate with the person who is sitting in the LAN i.e LAN_CLIENT, as LAN's IP is not the same as that of internet. Both are using winsock control of VB 6 application(UDP).

Both users have to be connected directly i.e no server. So how the data of HOME_CLIENT will pass through LAN's server & reach LAN_CLIENT's PC.

I don't want to use port forwarding done manualy in router.
I'll be very thankful for the reply.

One solution is socket.

Kuphryn