Diagnose Active Directory Management Gateway Service (ADMGS) Errors

I recently worked on a Windows Server 2008 system with the Active Directory Management Gateway Service (ADMGS) installed. The ADMGS allows you to use the Active Directory module for Windows PowerShell to manage AD remotely in domains where there are no Server 2008 R2 domain controllers running.

The ADMGS service (which runs as the Active Directory Web Services, ADWS, service) worked fine for several months but decided to begin having problems recently. We saw the following error message when running the “import-module activedirectory” command in PowerShell

The server was unable to process the request due to an internal error. For more information about the error, either turn on IncludeExceptionDetailInFaults (either from ServiceBehaviorAttribute or from the <serviceDebug> configuration behavior) on the server in order to send the exception information back to the client, or turn on tracing as per the Microsoft .NET Framework 3.0 SDK documentation and inspect the server trace logs.

Needing to troubleshoot the source of the issue, I messed with the IncludeExceptionDetailInFaults attribute in the C:WindowsADWSMicrosoft.ActiveDirectory.WebServices.exe.config file. However, this proved to be a daunting task for a number of reasons so I moved on to another solution. (View an example of setting the IncludeExceptionDetailInFaults attribute.)

Finally, I located a post that helped break this open. Adding a couple of debug keys in the <AppSettings> section of the config file allowed me to log the ADMGS error on the server and diagnose the real source of the error.

<add key="DebugLevel" value="Info" />
<add key="DebugLogFile" value="C:WindowsDebugadws.log" />

Use the following valid string values (not numeric values) for the DebugLevel value.This will add diagnostic info into the debug log at the DebugLogFile path you specify.

  • 0 – No logging
  • 1 – Error (this logs critical errors only)
  • 2 – Warn (this logs warning events as well as error events) – Recommended value to use unless you need full tracing
  • 3 – Info (verbose)

Once I set up debugging and restarted the ADMGS service, I got to the bottom of the problem with the error below and I can now address the permissions issue that is causing connection problems with the “import-module activedirectory” PowerShell command.

ActiveDirectoryWebServices: [xx/xx/2011 6:14:15 PM] [3] Get: Unhandled Exception System.UnauthorizedAccessException: Access to the temp directory is denied. Identity 'YOUR_DOMAINYourAccount' under which XmlSerializer is running does not have sufficient permission to access the temp directory. CodeDom will use the user account the process is using to do the compilation, so if the user doesnt have access to system temp directory, you will not be able to compile. Use Path.GetTempPath() API to find out the temp directory location.