C# – Connect to remote computer using WMI and C#

cwmi

Hy… I am trying to connect to a remote computer using WMI and C#.
I get an error: The RPC server is unavailable. (Exception result HRESULT: 0x800706BA).
I don't know if that is code related so this is what I'm using:

serverN = InputText.Text;//serverN=IPAddress
userN = userName.Text;
passN = passName.Text;
if (String.IsNullOrEmpty(serverN))
                serverN = ".";
ManagementClass manC = new ManagementClass("Win32_LogicalDisk");
string strScope = string.Format(@"\\{0}\root\cimv2", serverN);
ConnectionOptions conOpt = new ConnectionOptions();
conOpt.Username = userN;
conOpt.Password = passN;
manC.Scope = new ManagementScope(strScope, conOpt);

When I try to get instances from manC I catch the exception with the RPC being unavailable.
Locally it works so I'm guessing that I have to make some settings on the remote machine (OS: Windows XP sp2).
I have checked so that it allows remote connections and I have inserted command netsh firewall set service RemoteAdmin into command prompt.
Do I need to set a domain name or a networkid?
Or it is something else I'm missing?

Best Answer

I know it might be late for you, but for others who might stumble on this post: If you're sure it is not a user rights issue (you know the folder has the permissions) Check what you're giving as AuthenticationLevel to the ConnectionOptions object. I iterated through every one of them and for me the only that works is the PacketPrivacy option.

ConnectionOptions conOp = new ConnectionOptions();
conOp.Authentication = System.Management.AuthenticationLevel.PacketPrivacy;

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

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

Best Answer

Related Solutions

C# – the difference between String and string in C#

This is the style that Microsoft tends to use in their examples.

C# – “Access is denied” Exception with WMI

Related Topic