What is iis

Last updated: April 1, 2026

Quick Answer: IIS stands for Internet Information Services, a web server software developed by Microsoft. It hosts websites and web applications on Windows servers and is one of the most widely used web servers globally.

Key Facts

What is Internet Information Services

IIS (Internet Information Services) is a web server developed by Microsoft that processes HTTP requests and delivers web content to users. It runs on Windows Server and Windows operating systems, managing websites, web applications, and web services. IIS is a core component of the Microsoft web platform stack.

History and Development

Microsoft introduced IIS in 1995 with Windows NT 3.51. Initially called "Internet Information Server," it was renamed to Internet Information Services in Windows 2000. Over three decades, IIS has evolved from a basic web server to a sophisticated application platform. Current versions support modern frameworks and cloud deployments.

Key Features

IIS provides comprehensive web server functionality including request handling, authentication, caching, and compression. The server supports multiple authentication methods: Basic, Digest, Windows Authentication, and Forms-based authentication. IIS includes built-in SSL/TLS support for secure HTTPS connections. Application pool isolation ensures stability when multiple applications run on the same server.

Supported Technologies

IIS hosts applications written in ASP.NET, ASP.NET Core, PHP, Node.js, and Java. This flexibility makes IIS suitable for diverse development environments. The server can run classic ASP applications alongside modern .NET applications. Static file serving and dynamic content generation are both handled efficiently.

Global Usage and Market Share

Approximately 10% of websites globally use IIS according to web server statistics. Fortune 500 companies often deploy IIS for mission-critical applications. Government agencies and financial institutions rely on IIS for security and reliability. While Apache and Nginx dominate Linux environments, IIS maintains significant market presence in Windows-based infrastructure.

Related Questions

What is the difference between IIS and Apache?

IIS is Microsoft's web server for Windows, while Apache is open-source and cross-platform. IIS integrates with Windows authentication and Active Directory, whereas Apache is more common on Linux systems and offers greater flexibility.

How does IIS work with ASP.NET?

IIS hosts ASP.NET applications and passes HTTP requests to the .NET runtime for processing. IIS manages the application lifecycle, authentication, and response delivery, making it the standard deployment platform for ASP.NET applications.

Is IIS free to use?

IIS is included free with Windows Server operating systems. Desktop versions of Windows also include IIS, though functionality may be limited. You only pay for the Windows Server license itself.

Sources

  1. Microsoft IIS Official Documentation Commercial
  2. Wikipedia - Internet Information Services CC-BY-SA-4.0