|Select the web application under the web site to show the Features View of the web application.|
|Double-click the Authentication feature to open the Authentication view.
|Select Forms Authentication in the view and then click the “Edit…” link to bring up the Forms Authentication Settings dialog window.
|Enter your value in the “Authentication cookie time-out (in minutes):” box.|
|Return to the Features View of the web application.
|Double-click the Session State feature to open the Session State view.
|Enter your value in the “Cookie Settings” -> “Time-out (in minutes):” box. Then click the “Apply” link in the upper right.|