A network location server installed on the internal network is used to determine whether a DirectAccess client is connected to the internal network. When a DirectAccess client connects to a network, it attempts to access the specified HTTPS based URL on a network location server that was configured in the Forefront UAG DirectAccess Configuration Wizard. If the connection to the HTTPS based URL is successful, the DirectAccess client determines that it is on the internal network, and DirectAccess functionality is not used. If the network location server is unavailable, and the DirectAccess client is connected to the internal network, DirectAccess functionality is enabled for the client, and this impairs the client's ability to reach internal network resources.
At least on a daily basis you should confirm that the network location server is functioning.
To verify that the network location server is functioning
On a DirectAccess client located on the intranet, from the taskbar, click the Internet Explorer icon.
In the Address bar, type the HTTP based URL configured in the Forefront UAG DirectAccess Configuration Wizard. For example, https://nls.corp.contoso.com/, and then press ENTER. You should see the Web page you configured on the network location server.