We must know about TCP Proxy Server
Once you get the programs running, you should study the code and try to understand it.
A TCP proxy server is a server which acts as an intermediary between a client and another server, called the destination server. Clients establish connections to the TCP proxy server, which then establishes a connection to the destination server. The proxy server sends data received from the client to the destination server and forwards data received from the destination server to the client. Interestingly, the TCP proxy server is actually both a server and a client. It is a server to its client and a client to its destination server.
And than a TCP proxy server can be useful to get around services which restrict connections based on the network addresses. For example, there are many servers at MIT which will only serve data to addresses within the MIT network. By running a proxy server on the MIT network, clients from outside MIT can use those servers by connecting through the proxy server. The MIT servers will think they are serving data to a machine on the MIT network (namely the proxy server machine) and they'll be right. However, the proxy is forwarding the data out of the MIT subnet, thus subverting the protection mechanism. This is a violation of the rules of use on most of those server, so we do not encourage you to do this.
