Get / Display mac addresses

 public static string GetMacAddress(string separator = ":")
        {
            //System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable()
            foreach (var ni in System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces())
            {
                var mac = ni.GetPhysicalAddress().ToString();

                for (int i = mac.Length - 2; i > 0; i -= 2)
                {
                    mac = mac.Insert(i, separator);
                }

                Console.WriteLine($"Interface: {ni.Name} Mac {mac}");
            }
            string.Empty;
        }