How to configure authentication in IIS, you follow these steps:

• First start IIS manager or open the IIS snap-in.
• Just expand the server name where server name is the name of the server> then expand web sites.
• In the console tree > right-click the web site > virtual directory or file for which you want to configure authentication > click Properties.
• Press the directory security > under anonymous and access control > press Edit.
• Press to select the check box next to the authentication method or methods that you want to use >at the last you just press ok.

There is another type of authentication based on the requesting host instead of on user credentials.
 To configure this type of authentication, follow these steps:

• To deny access > press Granted Access > press Add. In the Deny Access On dialog box that appears, specify the option that you want > press OK
• Press OK >quit IIS manager or close the IIS snap-in.
  

How to configure IIS after running setup on Windows Server 2003

For IIS configuration, you just follow these steps:

• Go to the Start menu button then press all programs.
• Press administrative tools > press Internet Information Services.
• Then Right-click your machine name in the left pane > click security.
• Press next > verify that HTTP is set to automatic > press next.
• In the request handlers list, check ASP.NET and each instance of <Microsoft.NET Framework install directory>\aspnet_isapi.dll.
• Press next and in the last step Finish to complete the wizard.

 Install IIS on a computer running Windows Server 2003 as a web server

To install IIS, add optional components or remove optional components, follow these steps:

• Press Start button in left pane > point to control panel > press add or Remove Programs >click Add/Remove Windows components.
• Click application server but do not select the check box.
• Press click details > press to select the Internet Information Services (IIS) check box.
• Press details to view the list of IIS optional components.
• Select the optional components that you want to install. By default, the following components are selected, common Files, Internet Information Services Manager, and World Wide Web Service.
• Press click World Wide Web Service > press details to view the list of IIS optional subcomponents such as the remote administration tool. Select the optional subcomponents that you want to install. By default World Wide Web Service.
• Press OK >press next to install the selected components.
• Press Finish to complete the Windows components wizard >close the Add or Remove Programs dialog box.

This article described that how a windows 2003 server user can configure IIS? You can configure IIS to authenticate users before they are permitted access to a Web site a folder in the site or even a particular document contained in a folder in the site.