What is iis?

IIS stands for Internet Information Services. It is a web server software created by Microsoft that runs on Windows operating systems. Think of it as a program that listens for requests from web browsers (like Chrome or Edge) and then sends back the web pages, files, or data those browsers ask for.

Let's break it down

  • Web server: A piece of software that handles HTTP requests and serves web content.
  • Windows‑only: IIS is built into Windows Server and some Windows client editions, so it works best on Microsoft platforms.
  • Modules: IIS is made up of small components (called modules) that add features such as security, logging, URL rewriting, and more.
  • Management tools: You can control IIS through a graphical interface (IIS Manager), command‑line tools, or scripts (PowerShell).
  • Supports many technologies: It can host static HTML sites, ASP.NET applications, PHP, and even serve as a reverse proxy for other services.

Why does it matter?

A web server is the backbone of any website or web‑based application. IIS matters because:

  • It integrates tightly with other Microsoft products (like Windows authentication, .NET, and Azure).
  • It provides a familiar, GUI‑driven way for administrators to set up and manage sites.
  • Many enterprise environments already run Windows servers, so IIS fits naturally into existing infrastructure.
  • It offers built‑in security features and performance optimizations that help keep sites fast and safe.

Where is it used?

  • Corporate intranets and internal web applications that run on Windows servers.
  • Public websites built with ASP.NET or .NET Core that need a Windows host.
  • Hosting providers that offer Windows‑based shared or dedicated hosting plans.
  • Development and testing environments for developers working with Microsoft technologies.
  • As a reverse proxy or load balancer in front of other services (e.g., forwarding requests to a Node.js app).

Good things about it

  • Deep Windows integration: Works seamlessly with Active Directory, Windows authentication, and other Microsoft services.
  • User‑friendly GUI: IIS Manager makes configuration accessible for beginners and seasoned admins alike.
  • Extensible: Modules and handlers let you add exactly the features you need without bloating the server.
  • Strong security: Built‑in request filtering, IP restrictions, and SSL/TLS support help protect sites.
  • Performance: Supports HTTP/2, caching, and compression out of the box, which can speed up content delivery.

Not-so-good things

  • Windows‑only: If your environment runs Linux or macOS, IIS isn’t an option.
  • Resource heavy: Compared to lightweight servers like Nginx, IIS can consume more CPU and memory.
  • Licensing costs: Full features often require Windows Server licenses, which can be pricey for small projects.
  • Learning curve for advanced features: While the GUI is simple, mastering modules, custom handlers, or PowerShell automation can be complex.
  • Less community support: The open‑source community around IIS is smaller than for Apache or Nginx, so finding tutorials or third‑party plugins may be harder.