What is Microsoft IIS?

Microsoft Internet Information Services (IIS) is a web server for hosting websites and web applications. Like other web servers, it accepts requests for web pages or web applications and responds with the appropriate data. It’s one of the most widely used web servers, outpaced only by Apache and Nginx. However, unlike Apache and Nginx, Microsoft IIS is not open source, and while it is free to use, it’s the only web server that runs exclusively on Windows.

Support for hosting ASP.NET web applications and websites is a distinguishing feature of IIS servers. Built-in support for the .NET software framework and ASP.NET web framework offers developers a collection of libraries and tools for building web applications and dynamic web pages.

IIS offers a suite of built-in authentication tools like Windows auth, Basic, and ASP.NET. Additionally, integration with Windows Active Directory provides a convenient means of authentication as domain account users are automatically signed in to web applications. IIS server can be configured to host web applications built using other languages such as PHP. A number of extensions are available to add features and functionality to IIS servers. Users can choose from extensions to aid developers, add publishing functionality, improve performance, manage and host applications, and much more.

Remote management is possible through a command line interface (CLI) or PowerShell. This simplified remote interface allows users to perform file operations and transfer data using a secure connection between a remote computer and the server. IIS servers can also function as an FTP server with a robust set of security options, 

WordPress and IIS

WordPress powers 43% of all websites on the internet, making it the most popular web publishing platform. IIS makes it easy to install WordPress using the Microsoft Web Platform Installer (Web PI) and its built-in Windows Web App Gallery. This free tool also lets you install the components required for hosting and serving WordPress sites, including IIS, PHP, and MySQL. 

Windows IIS vs Linux, Apache, and Nginx

Three different web servers power the majority of the internet, IIS, Apache, and Nginx. Each has its strengths and weaknesses, with the web development community often split on which is best under different circumstances or for specific tasks. IIS is the only proprietary software of the three, with all of the considerable support of software giant Microsoft thrown behind it. Even though Apache and Nginx are open-source and community-supported, their wide use and flexibility have a lot to offer.

IIS vs Apache

Apache development began in 1995, and by 2009 had become the most popular web server on the internet. While Nginx has surpassed Apache in terms of popularity, Apache remains a close second. Between the two web servers, they represent over 60% of the market share. As of 2022, Microsoft IIS servers control about 6%, a drastically smaller figure.

Part of Apache’s popularity over IIS may be due to its inherent flexibility. This open-source software is a part of the LAMP stack, which is typically composed of Linux, Apache, MySQL, and PHP. It’s one of the most common software packages used for web development.   

Many web developers choose Apache as its highly configurable, modular structure allows it to serve a wide variety of purposes. The availability of modules makes it easy to add features and functionality. It also offers support for many popular programming languages and server software. 

IIS vs Nginx

Nginx is also an open-source web server, first publicly released in 2004. It started as a way to improve load balancing and serve static files while working in front of Apache servers. Its initial ability to handle 10,000 concurrent connections brought great improvement to scalability issues. 

Nginx gradually replaced Apache as the top web server on the web due to its resource efficiency and performance. This highly scalable web server’s asynchronous, event-driven architecture is known for superior performance under heavy loads. When compared to IIS and Apache, Nginx outperforms both in terms of speed and efficiency.

Nginx can also work alongside other web servers as an HTTP cache or as a proxy server. For example, IIS and Nginx can work together, with Nginx running as a reverse proxy. However, Nginx’s performance on Windows is less impressive than it is on Linux. 

	IIS	Apache	Nginx
Usage stats (March 2022)	6.1%	30.8%	33.1%
Accessibility	Requires Windows. The operating system’s cost can potentially deter users.	Open-source and compatible with many computer systems and operating systems.	Open-source, cross-platform, and freely available.
Community and acceptance	Not as widely used, but well-documented and with available premium support.	A huge community of knowledgeable developers and users is available to help solve issues.	Optional email support or forum-based support from a large, helpful community.
Resource usage	Generally accepted as efficiently using resources, particularly when streaming media.	Faster than IIS, but can be more resource-intensive. Apache’s multi-functional nature can possibly hinder performance.	Efficiently scales even limited resources due to Nginx’s asynchronous, event-driven architecture. Has the ability to handle a large number of concurrent connections.
Features & Functionality	Add components, features, and tools with Web PI and Windows App Gallery.	Easily add or remove modules to extend functionality.	Provides wide support for popular web apps but it may be more difficult to install and configure Nginx.
Integration with Windows and Microsoft products	Deep integration with Windows and some MS products and services.	Although Apache is compatible with Windows, the lack of integration could be a drawback for businesses that rely on Microsoft products.	Works with Windows and IIS as a proxy server, but with notably lower performance compared to Nginx on Linux-based systems.
Flexibility	IIS is designed around the .NET and .ASP frameworks, but can be configured to support other programming languages and web apps.	Highly configurable for a variety of specific needs.	Wide compatibility for different operating systems. Supports all popular web apps. Errors may be more challenging to track down, however.
Compatibility	Moving away from IIS could be challenging.	Works with many popular databases and programming languages. Supports many types of server software.	Compatible with Windows and Linux-based systems. Runs a variety of popular server software smoothly.
Security	Windows is the most popular target for malicious attacks. IIS is often considered less secure than Apache.	The many modules and config files associated with Apache must all be watched carefully to prevent security issues.	Considered to have a secure codebase and offers strong security when properly configured.
WordPress	Many different pre-configured one-click WordPress installations are available through the Azure marketplace and Web PI.	Works out of the box with WordPress. Easy one-click WordPress installs are available through tools like Bitnami.	Highly compatible with WordPress, particularly for static WordPress sites. Many large sites use Nginx and FastCGI caching to serve dynamic web pages.