ets) The Windows programming interface to TCP/IP, which is the communications protocol of Unix networks and the Internet. Windows network applications that communicate via TCP/IP are Winsock compliant as are the implementations of the TCP/IP protocol from Microsoft and third parties.
The WINSOCK.DLL file is included with all Windows versions subsequent to Windows 3.1. Early Internet applications often installed the DLL to ensure its existence. See TCP/IP
and Berkeley sockets