ProxyChains is a tool that forces any TCP connection made by any given application to go through proxies like TOR or any other SOCKS4, SOCKS5 or HTTP proxies. It is an open-source project for GNU/Linux systems.

Essentially, you can use ProxyChains to run any program through a proxy server. This will allow you to access the Internet from behind a restrictive firewall, hide your IP address, run applications like SSH/ telnet/wget/FTP and Nmap through proxy servers, and even access your local Intranet from outside through an external proxy.