Secure RPC Traffic Problem When Using RPC Ping Tool

The remote procedure call (RPC) Ping tool may not work when the Run with Security option is selected.

This behavior occurs because the NT LM Security Support Provider service could not start. Note that if you attempt to start the NT LM Security Support Provider service by using the Services tool in Control Panel, you may receive the following error message:

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.

1. Start Registry Editor (Regedt32.exe).
2. Locate the values under the following key in the registry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_NTLMSSP
3. If the values under this key are missing or corrupted, delete the key (LEGACY_NTLMSSP).
4. Quit Registry Editor.
5. Restart the computer.

The RPC Ping utility is often used to check RPC connectivity problems when you are troubleshooting Microsoft Outlook/Microsoft Exchange client-server communications.

Outlook/Exchange clients use a secure RPC connection when connecting to an Exchange server. When you are testing with the RPC Ping tool (Rpingc32.exe), the Run with Security option is often used to make sure a secure RPC connection can be made with the server.

If the RPC test without selecting the Run with Security option works, but does not work if security is used, verify whether the NT LM Security Support Provider service is started or can be started manually.

When you use Network Monitor to capture network traffic, you may not see any network traffic coming from a client having this problem.