dissecting WMI

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Over the past few days, I have been busy trying to figure out what WMI is and how we could possibly implement it in Samba.

WMI is Microsofts' implementation of the WBEM standard; unlike most other vendors, it however does not use the CIM-XML but DCOM.

I did a quick capture of the network traffic when running the following script:

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For Each Host In WScript.Arguments
   Set WMIservice = GetObject("winmgmts:{impersonationLevel=impersonate}!\\\\" & host & "\root\cimv2")

   Set colsettings = WMIservice.ExecQuery("SELECT * FROM Win32_Processor")

   For Each proc In colsettings
       Wscript.Echo(host & ": " & proc.description)
   Next
 Next

It appears WMI uses just the very simple set of DCOM interfaces (IOXIDResolver, IRemUnknown2, IRemUnknown, ISystemActivator) combined with a small number of WMI-specific interfaces.

This means that implementing the client-side of WMI will be relatively easy - once I get DCOM working fully again, it should just be a matter of adding the ODL for the required interfaces.

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