When you want Web site content to expire automatically such that no obsolete information is cached at the proxy or Web browsers you configure Content expiration in IIS at the Web site level. In IIS 6.0 Right click on Web Site (Default Web Site in our case) and click on Properties Under HTTP Headers tab you can check Enable content expiration   In IIS 7 / 7.5 Click on the Web Site (Default Web Site in our case) In the Features View, double click HTTP Response Hea... [More]