In C# how to find the mac address of internal devices not the Router mac address

Question

I want to get the mac address of my software user on the network due to some security reasons. But i am able to get the mac address of the router through following method.

public string GetMACAddress()
    {
        NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
        String sMacAddress = string.Empty;
        foreach (NetworkInterface adapter in nics)
        {
            if (sMacAddress == String.Empty)// only return MAC Address from first card  
            {
                IPInterfaceProperties properties = adapter.GetIPProperties();
                sMacAddress = adapter.GetPhysicalAddress().ToString();
            }
        } return sMacAddress;
    }

I need the specific mac address of the system that access my software on the internet and the internal device of that router. is that possible through C#?

Answer 1

This Works for me.!

string macAddress = NetworkInterface
.GetAllNetworkInterfaces()
.Where( nic => nic.OperationalStatus == OperationalStatus.Up && nic.NetworkInterfaceType != NetworkInterfaceType.Loopback )
.Select( nic => nic.GetPhysicalAddress().ToString() )
.FirstOrDefault();

Answer 2

static string GetMacAddress()
{
    string macAddresses = "";
    foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces()) {
        // Only consider Ethernet network interfaces, thereby ignoring any
        // loopback devices etc.
        if (nic.NetworkInterfaceType != NetworkInterfaceType.Ethernet) continue;
        if (nic.OperationalStatus == OperationalStatus.Up) {
            macAddresses += nic.GetPhysicalAddress().ToString();
            break;
        }
    }
    return macAddresses;
}

Taken from here , just one quick google away.

Answer 3

This method is the best way to get Mac address of your User.

[DllImport("Iphlpapi.dll")]
        private static extern int SendARP(Int32 dest, Int32 host, ref Int64 mac, ref Int32 length);
        [DllImport("Ws2_32.dll")]
        private static extern Int32 inet_addr(string ip);
        private static string GetClientMAC(string strClientIP)
        {
            string mac_dest = "";
            try
            {
                Int32 ldest = inet_addr(strClientIP);
                Int32 lhost = inet_addr("");
                Int64 macinfo = new Int64();
                Int32 len = 6;
                int res = SendARP(ldest, 0, ref macinfo, ref len);
                string mac_src = macinfo.ToString("X");

                while (mac_src.Length < 12)
                {
                    mac_src = mac_src.Insert(0, "0");
                }

                for (int i = 0; i < 11; i++)
                {
                    if (0 == (i % 2))
                    {
                        if (i == 10)
                        {
                            mac_dest = mac_dest.Insert(0, mac_src.Substring(i, 2));
                        }
                        else
                        {
                            mac_dest = "-" + mac_dest.Insert(0, mac_src.Substring(i, 2));
                        }
                    }
                }
            }
            catch (Exception err)
            {
                throw new Exception("Lỗi " + err.Message);
            }
            return mac_dest;
        }