A proxy server is, essentially, a computer on the internet with its own IP address. It sits between a network client and a remote server while acting as an intermediary to handle requests. When a user request comes into a firewall or proxy, it is accepted for processing. The incoming request is forwarded to a backed server which processes the request, the results of which are then forwarded to the requesting client. Proxy port thus is the port setup on the server handling incoming client requests. This hides access to the IP and port of the backend server.