IIS (Internet Information Server) is one of the most powerful web servers from Microsoft that is used to host your Web application. IIS has it's own Process Engine to handle the request. So, when a request comes from client to server, IIS takes that request and process it and send the response back to clients. Internet Information Services (IIS) is a flexible, general-purpose web server from Microsoft that runs on Windows systems to serve requested HTML pages or files. An IIS web server accepts requests from remote client computers and returns the appropriate response.