The service integrated into the Microsoft Windows 2000 Server operating system platform that provides support for application-layer Internet protocols. In the earlier Windows NT Server platform, IIS stood for “Internet Information Server” and was an optional component of Windows NT Server.
Internet Information Services (IIS) is also the foundational component for a wide variety of Microsoft Internet and intranet solution platforms, including Microsoft Site Server, Microsoft Commercial Internet System (MCIS), and other Microsoft BackOffice products.
IIS has evolved since it was first released for Windows NT 3.51 into its current version 5.0 for the Windows 2000 platform. The highest version available for the Windows NT platform is version 4.01, which was included as part of the Windows NT Option Pack. Both IIS versions 4.01 and 5.0 support the following features: