SOCKS

SOCKS is an Internet protocol that exchanges network packets between a client and server through a proxy server. SOCKS5 additionally provides authentication so only authorized users may access a server. Practically, a SOCKS server proxies TCP connections to an arbitrary IP address, and provides a means for UDP packets to be forwarded. SOCKS is an Internet protocol that exchanges network packets between a client and server through a proxy server. SOCKS5 additionally provides authentication so only authorized users may access a server. Practically, a SOCKS server proxies TCP connections to an arbitrary IP address, and provides a means for UDP packets to be forwarded. SOCKS performs at Layer 5 of the OSI model (the session layer, an intermediate layer between the presentation layer and the transport layer). SOCKS server accepts incoming client connection on TCP port 1080. The protocol was originally developed/designed by David Koblas, a system administrator of MIPS Computer Systems. After MIPS was taken over by Silicon Graphics in 1992, Koblas presented a paper on SOCKS at that year's Usenix Security Symposium, making SOCKS publicly available. The protocol was extended to version 4 by Ying-Da Lee of NEC. The SOCKS reference architecture and client are owned by Permeo Technologies, a spin-off from NEC. (Blue Coat Systems bought out Permeo Technologies.) The SOCKS5 protocol was originally a security protocol that made firewalls and other security products easier to administer. It was approved by the IETF in 1996. The protocol was developed in collaboration with Aventail Corporation, which markets the technology outside of Asia. SOCKS is a de facto standard for circuit-level gateways. Another use of SOCKS is as a circumvention tool, allowing traffic to bypass Internet filtering to access content otherwise blocked, e.g., bygovernments, workplaces, schools, and country-specific web services. Some SSH suites, such as OpenSSH, support dynamic port forwarding that allows the user to create a local SOCKS proxy. This can free the user from the limitations of connecting only to a predefined remote port and server. The Tor onion proxy software presents a SOCKS interface to its clients.