Hello everyone,
I don't know what is the exact name to call this, so I call based on what I want to do in my program. Its operation got something similar to chat server and client.
I have server and client application. Firstly, when one client connects to server and request a file from database, server then will check the database, to see whether any client who has the requested file is online. If he is online, server will send IP address of both clients to each other, and connection between them establish.
I can create connection between server and client, but don't know whether can establish another connection between client and client in the same program or not. Using socket, if can, what do I need to use?

Obviously, you can't establish peer-to-peer connection between independent client processes from your server application.