Hi. I'm a programmer from Russia with strong skills in C++. You can see the full list of my skills on my profile page. I have strong experience in developing such projects: I performed applications that use TCP protocol and HTTP requests. I plan to implement your task using Qt library. It provides very convenient tools for network managing. Every connection will run in separate thread, so if one socket will be blocked, others will continue to work properly. The application will receive request for connections and redirect them to defined address and port. When predefined keyword appears in network stream, the app closes connection. That's an outline.
If you're interested, lets discuss the details via private mail.
Cheers,
Sergey.