ManagementClass mc;

            mc = new ManagementClass("Win32_NetworkAdapterConfiguration");

            ManagementObjectCollection moc = mc.GetInstances();

            foreach (ManagementObject mo in moc)

            {

                //if (mo["IPEnabled"].ToString() == "True")

                //    Console.WriteLine( mo["MacAddress"].ToString());

                  if (mo["IPEnabled"].ToString() == "True")

                    Console.WriteLine(mo["MacAddress"].ToString());

            }

            Console.Read();