public static string GetMacAddress()
        {
            string addr = "";
            int cb;
            TmphASTAT adapter;
            TmphNCB Ncb = new TmphNCB();
            char uRetCode;
            TmphLANA_ENUM lenum;

            Ncb.ncb_command = (byte)TmphNCBCONST.NCBENUM;
            cb = Marshal.SizeOf(typeof(TmphLANA_ENUM));
            Ncb.ncb_buffer = Marshal.AllocHGlobal(cb);
            Ncb.ncb_length = (ushort)cb;
            uRetCode = TmphWin32API.Netbios(ref Ncb);
            lenum = (TmphLANA_ENUM)Marshal.PtrToStructure(Ncb.ncb_buffer, typeof(TmphLANA_ENUM));
            Marshal.FreeHGlobal(Ncb.ncb_buffer);
            if (uRetCode != (short)TmphNCBCONST.NRC_GOODRET)
                return "";

            for (int i = 0; i < lenum.length; i++)
            {
                Ncb.ncb_command = (byte)TmphNCBCONST.NCBRESET;
                Ncb.ncb_lana_num = lenum.lana[i];
                uRetCode = TmphWin32API.Netbios(ref Ncb);
                if (uRetCode != (short)TmphNCBCONST.NRC_GOODRET)
                    return "";

                Ncb.ncb_command = (byte)TmphNCBCONST.NCBASTAT;
                Ncb.ncb_lana_num = lenum.lana[i];
                Ncb.ncb_callname[0] = (byte)'*';
                cb = Marshal.SizeOf(typeof(TmphADAPTER_STATUS)) + Marshal.SizeOf(typeof(TmphNAME_BUFFER)) * (int)TmphNCBCONST.NUM_NAMEBUF;
                Ncb.ncb_buffer = Marshal.AllocHGlobal(cb);
                Ncb.ncb_length = (ushort)cb;
                uRetCode = TmphWin32API.Netbios(ref Ncb);
                adapter.adapt = (TmphADAPTER_STATUS)Marshal.PtrToStructure(Ncb.ncb_buffer, typeof(TmphADAPTER_STATUS));
                Marshal.FreeHGlobal(Ncb.ncb_buffer);

                if (uRetCode == (short)TmphNCBCONST.NRC_GOODRET)
                {
                    if (i > 0)
                        addr += "-";
                    addr = string.Format("{0,2:X}-{1,2:X}-{2,2:X}-{3,2:X}-{4,2:X}-{5,2:X}",
                    adapter.adapt.adapter_address[0],
                    adapter.adapt.adapter_address[1],
                    adapter.adapt.adapter_address[2],
                    adapter.adapt.adapter_address[3],
                    adapter.adapt.adapter_address[4],
                    adapter.adapt.adapter_address[5]);
                }
            }
            return addr;
        }
 public static extern char Netbios(ref TmphNCB ncb);