Socket Secure (SOCKS) is an Internet Protocol that exchanges network packets between a client and server through a proxy server.

SOCKS version 5 is defined in RFC 1928 and additionally provides authentication so only authorized users may access a server.

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 is a de facto standard for circuit-level gateways.

SOCKS is as a circumvention tool, allowing traffic to bypass Internet filtering to access content otherwise blocked, e.g., by governments, 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 Server. This can free the user from the limitations of connecting only to a predefined remote port and server.

The Onion Router Proxy Server presents a SOCKS interface to its clients

SOCKS operates at a lower level than HTTP proxying.

SOCKS uses a handshake protocol to inform the proxy software about the connection that the client is trying to make, and then acts as transparently as possible, whereas a regular HTTP proxy may interpret and rewrite headers (say, to employ another underlying protocol, such as FTP; however, an HTTP proxy simply forwards an HTTP request to the desired HTTP server). Though HTTP proxying has a different usage model in mind, the CONNECT method allows for forwarding TCP connections; however, SOCKS proxies can also forward UDP traffic and work in reverse, while HTTP proxies cannot. HTTP proxies are traditionally more aware of the HTTP protocol, performing higher-level filtering (though that usually only applies to HTTP GET and HTTP POST methods, not the HTTP CONNECT method).

More Information#

There might be more information for this subject on one of the following:
  • [#1] - SOCKS - based on information obtained 2017-04-01-

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« This page (revision-5) was last changed on 23-Apr-2017 10:41 by jim