SOCKS is a package consisting of a proxy server, client programs, and a library (libsocks) for adapting other applications into new client programs.
The original SOCKS was written by David Koblas (koblas@netcom.com). The SOCKS protocol has changed over time. The client library shipped as of printing corresponds to SOCKS v4.2. Since the server and the clients must use the same SOCKS protocol, this library doesn't work with servers of previous releases; clients compiled with these libraries won't work with older servers.