How to Disable SAP Broadcast for RPC Service (171307)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

On a computer running Windows NT Server, if Gateway Services for NetWare (GSNW) is installed, a SAP Type 640 broadcasts every 60 seconds by the remote procedure call (RPC) service. This SAP broadcast continues even if the user disables the GSNW and the SAP Agent Service.

On a computer running Windows NT Workstation, the RPC service does the SAP broadcast if the Client Services for NetWare (CSNW) and the SAP Agent service are installed. This SAP broadcast continues even if the user disables the SAP agent.

CAUSE

By default, the RPC service checks for the presence of Gateway Services for NetWare and the SAP Agent service on the computer running Windows NT Server.

On the computer running Windows NT Workstation with CSNW, the RPC service checks for the SAP Agent service. If the services are present, RPC starts its own thread that does the SAP broadcast Type 640 every minute.

RESOLUTION

Windows NT Server 4.0, Terminal Server Edition

To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734 How to Obtain the Latest Windows NT 4.0 Service Pack

Windows NT Server or Workstation 4.0

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:

http://www.microsoft.com/windows/servicepacks/ -or-
152734how to obtain the latest windows nt 4.0 service pack

For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

STATUS

Windows NT Server 4.0, Terminal Server Edition

Microsoft has confirmed that this is a problem in Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT Server 4.0, Terminal Server Edition Service Pack 6.

Windows NT 4.0

Microsoft has confirmed that this is a problem in Windows NT 4.0. This problem was first corrected in Windows NT 4.0 Service Pack 5.

MORE INFORMATION

After applying this fix, perform the steps below to create a new registry value.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Run Registry Editor (Regedt32.exe).

Go to the following key in the registry:

      HKEY_LOCAL_MACHINE\Software\Microsoft\RPC

On the Edit menu, click Add Value and use the following entry:
```
      Value Name: AdvertiseRpcService
      Data Type:  REG_SZ
      String:     No
						
```
Using No for the string turns RPC sapping off.
Using Yes for the string turns RPC sapping on.
Restart the computer for the registry change to take effect.

If the SAP broadcasts continue after following these steps, you may want to disable SAP broadcasts as a troubleshooting step. To disable SAP broadcasts, delete the Ncacn_spx string value in following registry key:

   HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\ServerProtocols\

NOTE: This should be used only as a troubleshooting step. Deleting this string value completely disables SAP broadcasts which some programs may need in order to function properly.

For additional information about, please see the following article in the Microsoft Knowledge Base:

142533 0x640 SAP Packets Increase Using Remote Registry Service