Using Content Expiration (IIS 6.0)
If you have time-sensitive information on your Web site, you can configure settings that will ensure that obsolete information isn't cached by proxies or Web browsers. You can configure Web site content to automatically expire at any time. When content expiration is enabled, the Web browser compares the current date to the expiration date to determine whether to display a cached page or request an updated page from the server. Server-side technology, such as Microsoft ASP.NET can be used to dynamically change the content served. Typically, time-sensitive information is limited to individual files, directories, or Web sites; however, you can also set content expiration for all Web sites on a computer.
You must be a member of the Administrators group on the local computer to perform the following procedure or procedures. As a security best practice, log on to your computer by using an account that is not in the Administrators group, and then use the runas command to run IIS Manager as an administrator. At a command prompt, type runas /User:Administrative_AccountName "mmc systemroot\system32\inetsrv\iis.msc".
To set the expiration of Web site content
To verify that expiration dates are working correctly, look for Not Modified messages in the HTTP response packet of your Network Monitor capture summary.