Web server is a computer program that is responsible for accepting HTTP requests from clients, which are known as Web browsers, and serving them HTTP responses along with optional data contents, which usually are Web pages such as HTML documents and linked objects (images, etc.). IIS is a web server which sits on the top of the ASP.NET engine which processes the HTML pages, images, etc. Configuring IIS with web application is the key for the performance and security for the ASP.NET pages. In this article we tried to explore various components of IIS. We also saw different Authentication standards of IIS.