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Microsoft Internet Information Services (IIS) Basics

written by: John Garger•edited by: Michele McDonough•updated: 8/22/2010

Hosting Internet services such as web pages, e-mail, and ftp requires software to serve information to Internet users. Although not the most popular alternative, Microsoft’s IIS is a major player in the Internet services market.

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    Most Internet users are unaware of the number of elements that come together to deliver web services at lightning-fast speeds to their computer. For example, when a web page is requested by an Internet surfer, a series of services along the path to the web pages relays the details of the request and returns the result in just few seconds. Chances are that one group of services published by Microsoft Corporation had something to do with resolving the request.

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    Brief History

    Microsoft’s Internet Information Services (IIS) was originally published as Internet Information Server 1.0 and was available as an add-on for the Windows NT 3.51 operating system. Versions 2.0, 3.0, and 4.0 were available on different variations of Windows NT. Version 5.0 shipped with Windows 2000 and the upgraded version 5.1 was first introduced with Windows XP Professional. Version 6.0 was available with Windows Server 2003 and Windows XP Professional x64 Edition. The latest 7.0 version of IIS is available with Windows Server 2008, Windows Vista, and is scheduled to be available on Windows 7.0 whose release date has not yet been announced.

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    What is IIS?

    IIS is a group of software that allows a user to run server-side services and collectively act as a full-featured web server. The services included in IIS 7.0 are File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), Hypertext Transfer Protocol over Secure Socket Layer (HTTPS), Network News Transfer Protocol (NNTP), and Simple Mail Transfer Protocol (SMTP). This version also ships with various modules that include security, compression, caching, and logging and diagnostic functions.

    IIS is the number two web server in world, second only to Apache HTTP Server. The latest data (November 2008) from Netcraft indicates that IIS commands about 35% of the market share for top servers across all domains. Apache, the number one web server, accounts for about 51%. Google is a distant third with only about 6% of the market share and Lighttpd has about 2%. Recent trends since early 2006 indicate that the gap between Microsoft and Apache is closing.

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    Media Pack

    The free IIS Media Pack is available for web servers running IIS 7.0 and includes modules for hosting and serving video and audio content. These modules allow servers to progressively serve multimedia so users can begin experiencing the media while the download is still in progress. One technology available with the IIS Media Pack is Bit Rate Throttling which quickly downloads a sufficient portion of the beginning of media content so playback can start immediately and then adjusts the remaining download to the bit rate of the media. This allows the media to be available to the client quickly and then throttles back the upload to match the media stream. This has the effect of reducing bandwidth waste which is a problem with the traditional send-and-forget paradigm of earlier packages.

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    IIS is a complete package of web services that ships with several versions of the Microsoft Windows operating system. The services allow a webmaster to serve content to Internet users in a secure and stable environment. IIS represents the second most commonly used web server, second only to Apache. However, the gap is closing between these two competitors as more and more web administrators adopt IIS as a web server platform.