Datasheet

IIS Versions 1.0 to 4.0
IIS was released with Service Pack 3 for Windows NT 3.51, as a set of services providing HTTP, Gopher,
and WAIS functionality. Although the functions were there, most users chose alternates from third-party
vendors such as O’Reilly’s Website or Netscape’s server. Although these services had been available for
years with the various flavors of UNIX operating systems, native Internet services for Windows were
mostly an afterthought, with little integration with the Windows operating system.
With the advent of Windows NT 4.0, IIS also matured in version 2.0. The most notable improvement in
IIS version 2.0 was closer integration with the Windows NT operating system, taking advantage of
Windows security accounts and providing integrated administration through a management console
similar to many other Windows services. IIS 2.0 introduced support for HTTP Host headers, which
allowed multiple sites to run on a single IP address, and aligned Microsoft’s IIS development with
NCSA standards, providing for NCSA common log formats and NCSA-style map files. IIS 2.0 also intro-
duced a web browser interface for management, and content indexing through Microsoft’s Index Server.
IIS version 3.0 was introduced with Windows NT Service Pack 3 and introduced the world to ASP
(Active Server Pages) and Microsoft’s concept of an application server. A precursor to the ASP.NET envi-
ronment, ASP (now referred to as classic ASP) is a server-side scripting environment for the creation of
dynamic web pages. Using VBScript, JScript or any other active scripting engine, programmers finally
had a viable competitor to CGI and scripting technologies available on non-Microsoft platforms, such as
Perl.
IIS 4.0, available in the NT Option Pack, introduced ASP 2.0, an object-based version of ASP that included
six built-in objects to provide standardized functionality in ASP pages. IIS 4.0 was the last version of IIS
that could be downloaded and installed outside of the operating system.
IIS 5.0 and 5.1
With the release of Windows 2000, IIS became integrated with the operating system. Version numbers
reflected the operating system, and there were no upgrades to IIS available without upgrading the oper-
ating system. IIS 5.0 shipped with Windows 2000 Server versions and Windows 2000 Professional, and
IIS version 5.1 shipped with Windows XP Professional, but not Windows XP Home Edition. For all
essential functions, IIS 5.0 and IIS 5.1 are identical, differing only slightly as needed by the changes to
the operating system.
With Windows 2000 and IIS 5.0, IIS became a service of the operating system, meant to be the base for
other applications, especially for ASP applications. The IIS 5.0 architecture served static content, ISAPI
functions, or ASP scripts, with ASP script processing handed off to a script engine based on the file
extension. Using file extensions to determine the program that handles the file has always been a com-
mon part of Windows functionality, and in the case of ASP processing, the speed of serving pages was
increased by the automatic handoff of ASP scripts directly to the ASP engine, bypassing the static con-
tent handler. This architecture has endured in IIS to the current version.
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Part 1: Introduction and Deployment
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