This policy setting controls whether RPC clients authenticate with the Endpoint Mapper Service when the call they are making contains authentication information. The Endpoint Mapper Service on computers running Windows NT4 (all service packs) cannot process authentication information supplied in this manner. If you disable this policy setting, RPC clients will not authenticate to the Endpoint Mapper Service, but they will be able to communicate with the Endpoint Mapper Service on Windows NT4 Server. If you enable this policy setting, RPC clients will authenticate to the Endpoint Mapper Service for calls that contain authentication information. Clients making such calls will not be able to communicate with the Windows NT4 Server Endpoint Mapper Service. If you do not configure this policy setting, it remains disabled. RPC clients will not authenticate to the Endpoint Mapper Service, but they will be able to communicate with the Windows NT4 Server Endpoint Mapper Service. Note: This policy will not be applied until the system is rebooted. Countermeasure: Enable this policy setting. Potential Impact: RPC clients will be forced to authenticate before they can begin communicating with the desired RPC service, this means that anonymous access will not be available and RPC clients that do not support authentication will fail. Fix: (1) GPO: Computer ConfigurationAdministrative TemplatesSystemRemote Procedure CallEnable RPC Endpoint Mapper Client Authentication (2) REG: HKEY_LOCAL_MACHINESoftwarePoliciesMicrosoftWindows NTRpc!EnableAuthEpResolution

[enabled/disabled]

(1) GPO: Computer Configuration\Administrative Templates\System\Remote Procedure Call\Enable RPC Endpoint Mapper Client Authentication (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Rpc!EnableAuthEpResolution