SOCKS

A SOCK is a protocol used for controlling the TCP traffic via a proxy server. We can use it with virtually TCP application such as Web browsers and FTP clients. This protocol serves as a useful firewall as it checks the inward as outward packets while hiding the IP addresses of client applications.
A SOCK is available in two versions i.e. V4 and V5. V5 adds the authentication mechanism pertaining to additional security features. There also exist number freeware implementations of the SOCKS versions. SOCKS5 is the most frequently used implementation evolved by NEC.
Recently, SOCKS was accepted as the IETF standard and also documented in RFC 1928, 1929 as well as in 1961.