Internet 101

A TCP/IP stack provides support for the various protocols that make up TCP/IP. It functions as a conduit between the application at the top of the networking model and the network medium (i.e.: the network cable) at the bottom. On a Windows system, the key element of the TCP/IP stack is the Windows Sockets library, provided in a file called WINSOCK.DLL. All Internet applications require the presence of the WINSOCK.DLL file on the system where they are run, in order to access the Internet. Windows Sockets is not a protocol. Rather, it is an application programming interface (API) that uses TCP/IP for network communications. Windows Sockets is a universal conduit to the network that allows users the freedom to choose different browsers, FTP, news and mail clients, etc. Since all of the programs are written to the Windows Sockets specification, they are essentially interchangeable. A commercial TCP/IP product (such as Chameleon, for example) may include various client programs, but there is no reason why you can't use others, as long as the product provides a WINSOCK.DLL.

Windows NT and Windows 95 systems include a TCP/IP stack as an integrated part of the operating system. If it is not already being used, you must install it from the Network Control Panel. FTP and Telnet clients are included with the operating system, as is Internet Explorer 2.0 and a collection of TCP/IP utilities.
Windows 3.1 requires the use of an external TCP/IP stack, as there is none in the operating system. There are many commercial TCP/IP products available, which usually ship with a collection of Internet client programs and utilities. There is also a freeware stack, called Trumpet Winsock, which provides adequate functionality, but does not include the documentation and technical support of a commercial product. Using TCP/IP with Windows 3.1 is necessarily a matter of reverse engineering. An operating system like Windows 95, in which the TCP/IP stack is fully integrated, is far easier to install and configure, and provides better performance than an add-on system.