MAC Address Authorization

Applies To: Windows Server 2008, Windows Server 2008 R2

Media access control (MAC) address authorization functions in the same way as automatic number identification (ANI) authorization, but it is used for wireless clients and clients connecting to your network by using an 802.1X authenticating switch.

MAC address authorization is based on the MAC address of the network adapter installed in the access client computer. Like ANI authorization, MAC address authorization uses the Calling-Station-ID attribute instead of user name and password or certificate-based credentials to identify the user during the connection attempt.

MAC address authorization is performed when the user does not type in any user name or password, and refuses to use any valid authentication method. In this case, Network Policy Server (NPS) receives the Calling-Station-ID attribute, and no user name and password. To support MAC address authorization, Active Directory Domain Services (AD DS) must have user accounts that contain MAC addresses as user names.

MAC address authorization is enabled when you do the following:

  1. Enable MAC address authorization on access servers, such as wireless access points (APs).

  2. Enable unauthenticated access on the appropriate NPS network policy for MAC address-based authentication, and enable Password Authentication Protocol (PAP).

  3. In the Active Directory Users and Computers Microsoft Management Console (MMC) snap-in, create a user account for each MAC address for which you want to provide MAC address authorization. The name of the user account must match the MAC address of the network adapter installed in the computer from which the user is connecting. The format of the password assigned to the account is determined by the network access server vendor. Review the network access server documentation to determine the appropriate password.

  4. Set the User Identity Attribute registry value to 31 on the NPS server. This registry value location is: HKLM\SYSTEM\CurrentControlSet\Services\RemoteAccess\Policy

  5. To always use the MAC address as the user identity, on the NPS server set the Override User-Name registry value to 1. This registry value location is: HKLM\SYSTEM\CurrentControlSet\Services\RemoteAccess\Policy


Incorrectly editing the registry can severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.


For more information, see NPS: User Identity Attribute and NPS: Override User-Name.