Session maximum and minimum timeout

The Timeout property can be set in the Web.config file for an application using the timeout attribute of the sessionState configuration element, or you can set the Timeout property value directly using application code.

The Timeout property cannot be set to a value greater than 525,600 minutes (1 year). The default value is 20 minutes

The following code example sets the timeout session attribute to 30 minutes in the Web.config file.

<configuration>

  <system.web>

    <sessionState 

      mode="InProc"

      cookieless="true"

      timeout="30" />

  </system.web>

</configuration>