User Configuration\Administrative Templates\Windows Components\NetMeeting
Prevents users from changing the way calls are placed, either directly or via a gatekeeper server.
Note
The NetMeeting folder containing this policy is created by the Conf.adm administrative template. Conf.adm is included in Windows 2000, but does not load in Group Policy automatically. To display the NetMeeting folder, add the Conf.adm administrative template to Group Policy.