C#: How do I retrieve only network interfaces attached to physical network cards?

Question

In my C# program, I need to enumerate all network interfaces which are actual network cards (Wifi or Ethernet), meaning - the ones connected to actual physical devices, as opposed to VPN connections, etc.

I'm using NetworkInterface.GetAllNetworkInterfaces() to enumerate NetworkInterfaces, but I don't know how to filter those for physical devices...

https://msdn.microsoft.com/en-us/library/system.net.networkinformation.networkinterface.networkinterfacetype(v=vs.110).aspx ? — Daniel A. White, Jun 21 '18 at 17:34
No, that doesn't help. VPN connection register as "Ethernet", same as regular network cards. — user884248, Jun 21 '18 at 22:05
I need to figure out if the computer is running on a 1GB connection or an older 100MB connection. — user884248, Jun 21 '18 at 22:08
Please refer this link https://stackoverflow.com/a/65090230/9368328 to get only physical adapters — Tony Stark, Dec 02 '20 at 07:54

score 2 · Answer 1 · answered Jul 15 '19 at 02:19

The NIs with prefix "PCI" are physical NIs.

            NetworkInterface[] fNetworkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
            foreach (NetworkInterface adapter in fNetworkInterfaces)
            {
                string fRegistryKey = "SYSTEM\\CurrentControlSet\\Control\\Network\\{4D36E972-E325-11CE-BFC1-08002BE10318}\\" + adapter.Id + "\\Connection";
                RegistryKey rk = Registry.LocalMachine.OpenSubKey(fRegistryKey, false);
                if (rk != null)
                { 
                    string fPnpInstanceID = rk.GetValue("PnpInstanceID", "").ToString();
                    int fMediaSubType = Convert.ToInt32(rk.GetValue("MediaSubType", 0));
                    if (fPnpInstanceID.Length > 3 && fPnpInstanceID.Substring(0, 3) == "PCI")
                    {

                    }
                }
            }

Good idea, but may not fully correct. You should also consider the situation of USB adapters, PCMCIA, and so on. — J.C, Feb 17 '20 at 08:43
I fell in love with this solution! Thank you so much, @Shannon! — Dorin Baba, Dec 29 '20 at 21:43

Jake1164 · Answer 2 · 2018-06-22T11:08:57.773

You need to use the NetworkInterfaceType Enumeration.

The docs include a pretty decent example for figuring this out.

 public static void DisplayTypeAndAddress()
{
    IPGlobalProperties computerProperties = IPGlobalProperties.GetIPGlobalProperties();
    NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
    Console.WriteLine("Interface information for {0}.{1}     ",
            computerProperties.HostName, computerProperties.DomainName);
    foreach (NetworkInterface adapter in nics)
    {
        IPInterfaceProperties properties = adapter.GetIPProperties();
        Console.WriteLine(adapter.Description);
        Console.WriteLine(String.Empty.PadLeft(adapter.Description.Length,'='));
        Console.WriteLine("  Interface type .......................... : {0}", adapter.NetworkInterfaceType);
        Console.WriteLine("  Physical Address ........................ : {0}", 
                   adapter.GetPhysicalAddress().ToString());
        Console.WriteLine("  Minimum Speed............................ : {0}", adapter.Speed);
        Console.WriteLine("  Is receive only.......................... : {0}", adapter.IsReceiveOnly);
        Console.WriteLine("  Multicast................................ : {0}", adapter.SupportsMulticast);
        Console.WriteLine();
      }
   }

NetworkInterfaceType doesn't help me. For example, the Forticlient VPN connection registers as "Ethernet" - just like my actual network card. — user884248, Jun 21 '18 at 22:05
What about using adapter.GetIPProperties() to narrow down based on the adapter with the correct network IP settings? — Jake1164, Jun 22 '18 at 11:17

score 0 · Answer 3 · answered Jun 22 '18 at 11:29

You will have to dig though all the provided info, however, the Win32_NetworkAdapterConfiguration class will give you info about the configuration of your adapters e.g. ip addresses etc and the Win32_NetworkAdapter class provides 'static' information about each adapter (max speed, manufacturer etc).

string query = "SELECT * FROM Win32_NetworkAdapterConfiguration";
ManagementObjectSearcher moSearch = new ManagementObjectSearcher(query);
ManagementObjectCollection moCollection = moSearch.Get();// Every record in this collection is a network interface

foreach (ManagementObject mo in moCollection)
{
    // ....
}

This does not recognize USB adapters. me = sad – Dorin Baba Dec 29 '20 at 19:40 — Dorin Baba, Dec 29 '20 at 19:40

C#: How do I retrieve only network interfaces attached to physical network cards?

3 Answers3