C# – WMI: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA) throws when try to connect to remote machine

cnetwmi

I'm using the following code to connect to remote machine using WMI:

   ConnectionOptions connOptions = new ConnectionOptions();
            connOptions.Impersonation = ImpersonationLevel.Impersonate;
            connOptions.EnablePrivileges = true;
            connOptions.Username = "admin";
            connOptions.Password = "password";
            ManagementScope scope = new ManagementScope(String.Format(@"\\{0}\ROOT\CIMV2", remoteMachine), connOptions);
            scope.Connect();

I'm getting the following exception: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)

Checked all steps described in this knowledgebase article, everything is OK on remote machine.

User is Administrator on remote machine.

Tried Wbemtest tool, the same result

Does anyone has an idea what is happening?

Best Answer

If you under Win7 you must run app as an administrator. You can also try different values for connOptions.Impersonation property. Did you open RPC port on a remote machine? Try turning off firewall altogeter on both machines.

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C# – “Access is denied” Exception with WMI

Note:If you do not specify credentials, the credentials of the running user will be used and so these have to be valid to access the remote computer and usually, this account has to be an admin on the remote box (not for all objects, but just to be sure).

If you are logged in with a domain account, which is valid on both computers, it would work out-of-the-box.

If you are not in a domain environment, just specify credentials.

Try this:

ConnectionOptions co = new ConnectionOptions();
co.Impersonation = ImpersonationLevel.Impersonate;
co.Authentication = AuthenticationLevel.Packet;
co.Timeout = new TimeSpan(0, 0, 30);
co.EnablePrivileges = true;
co.Username = "\\";
co.Password = "";

ManagementPath mp = new ManagementPath();
mp.NamespacePath = @"\root\cimv2";
mp.Server = "";               ///Regard this!!!!

ManagementScope ms = new ManagementScope(mp, co);
ms.Connect();

ManagementObjectSearcher srcd;
srcd = new ManagementObjectSearcher  
(
    ms, new ObjectQuery("select * from Win32_DisplayConfiguration")
);

This is working all the time for me.

From my point of view, the problem occurs, because you are not specifying a remote computer in your ManagementPath. A ManagementPath, created with the defaults, always points to the local machine. And if you just specify credentials to the local computer, this is not allowed and always fails.

br--mabra

C# – Remote WMI connection

Maybe it's the missing 'EnablePrivileges':

scope.Options.EnablePrivileges = true;

From MSDN (ConnectionOptions.EnablePrivileges Property):

Gets or sets a value indicating whether user privileges need to be enabled for the connection operation. This property should only be used when the operation performed requires a certain user privilege to be enabled (for example, a machine restart).

Edit: If it doesn't work, try setting the ImpersonationLevel to 'Impersonate':

scope.Options.Impersonation = System.Management.ImpersonationLevel.Impersonate;

ImpersonationLevel Impersonate: Impersonate-level COM impersonation level that allows objects to use the credentials of the caller. This is the recommended impersonation level for WMI calls.

Best Answer

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C# – “Access is denied” Exception with WMI

C# – Remote WMI connection

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