What Is IIS?

Date First Published: 10th May 2022

Topic: Computer Networking

Topic: Network Software

Article Type: Computer Terms & Definitions

Difficulty Level: 6/10

Learn more about what IIS is in this article.

Short for Internet Information Services, IIS, originally called Internet Information Server, is a web server software that was released by Microsoft on 30th May 1995 and runs on Windows. It is written in C++ and is used for hosting websites and other files, accepting client requests and then returning them with an appropriate response. It provides a graphical user interface for managing websites and publishing them on the World Wide Web. The IIS managers allow settings to be altered, such as custom error pages, logging settings, security settings, performance optimisation, and default pages.

Note:

IIS is not to be confused with a hosting provider or a physical web server. IIS is a web server software that runs on most versions of Windows. It allows computers to act as web servers, in a similar way to Apache.

How Does IIS Work?

IIS works in the same way as other web server software. It makes use of the HTTP protocol to allow devices to communicate over the World Wide Web and exchange information between web servers and clients. It also supports FTP, which is used for uploading to and downloading files from a web server.

IIS sends both static HTML pages and dynamic PHP pages. When a visitor accesses a file, such as a webpage or an image, IIS sends the file to the user’s web browser. Any scripts that are found in the webpage run in the user’s web browser.

SMTP is supported on IIS, the protocol used for transferring email messages and NNTP, the protocol used for transferring Usenet articles, news, and files from one server to another.

Extensions

IIS also supports extensions. These add additional features to the web server. An example of an extension is WinCache, which temporarily stores a copy of PHP processes, enabling PHP scripts to run faster. There are streaming extensions that enable media, such as videos and audio to be streamed and delivered in realtime to visitors.

Versions

IIS is included with most versions of Windows and is a built-in software. The versions of IIS include:

• IIS 1.0 - Included with the first version of IIS that was released with Windows NT 3.51.
• IIS 2.0 - Included with Windows NT 4.0.
• IIS 4.0 - Included with Windows NT 4.0. It introduced the MMC-based administration application. Additionally, it was the first version where multiple web and FTP servers can be run at the same time.
• IIS 5.0 - Included with Windows 2000. This version dropped support for the Gopher protocol and introduced authentication methods as well as support for the WebDAV protocol.
• IIS 6.0 - Included with Windows Server 2003 and Windows XP Professional x64 Edition. This version added support for IPv6.
• IIS 7.0 - Included with Windows Server 2008 and Windows Vista. This version was completely redesigned and included new command-line management options as well as support for the .NET framework.
• IIS 7.5 - Included with Windows Server 2008 R2 and Windows 7. In order for it to be enabled, it is necessary for it to be turned on in Programs and Features. This version added support for TLS 1.1 and 1.2.
• IIS 8.0 - Included with Windows Server 2012 and Windows 8. This version introduces SNI (Server Name Indication) which allows multiple hostnames to use HTTPS from the same IP address.
• IIS 8.5 - Included with Windows Server 2012 R2 and Windows 8.1. This version introduces dynamic site activation and enhanced logging.
• IIS 10 - Included with Windows Server 2016 and Windows 10. This version includes HSTS (HTTP Strict Transport Security) support.