Microsoft manual ISA Server 2004 Configuration Guide 242

7.Read the information on the Local Authentication page, and click Next.

8.On the L2TP/IPSec Authentication page, put a checkmark in the Allow pre-shared key IPSec authentication as a secondary (backup) authentication method check box. Enter a key in the Use pre-shared key for authentication text box. In this example, use the key 123. Click Next.

ISA Server 2004 Configuration Guide 242