private void buttonStart_Click(object sender, EventArgs e)
        {
            if (comboBoxInterfaces.SelectedIndex == -1)
            {
                MessageBox.Show("Select an Interface to capture the packets.", "WIFI Sniffer",
                   MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            try
            {
                if (!continue_capturing)
                {
                    //Start capturing the packets...

                    buttonStart.Text = "&Stop";

                    continue_capturing = true;

                    //For sniffing the socket to capture the packets has to be a raw socket, with the
                    //address family being of type internetwork, and protocol being IP
                    mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.IP);

                    //Bind the socket to the selected IP address
                    mainSocket.Bind(new IPEndPoint(IPAddress.Parse(comboBoxInterfaces.SelectedItem.ToString()), 0));

                    //Set the socket  options
                    mainSocket.SetSocketOption(SocketOptionLevel.IP,            //Applies only to IP packets
                                               SocketOptionName.HeaderIncluded, //Set the include the header
                                               true);                           //option to true

                    byte[] byTrue = new byte[4] { 1, 0, 0, 0 };
                    byte[] byOut = new byte[4] { 1, 0, 0, 0 }; //Capture outgoing packets

                    //Socket.IOControl is analogous to the WSAIoctl method of Winsock 2
                    mainSocket.IOControl(IOControlCode.ReceiveAll,              //Equivalent to SIO_RCVALL constant
                        //of Winsock 2
                                         byTrue,
                                         byOut);

                    //Start receiving the packets asynchronously
                    mainSocket.BeginReceive(byte_data, 0, byte_data.Length, SocketFlags.None,
                        new AsyncCallback(OnReceive), null);
                }
                else
                {
                    buttonStart.Text = "&Start";
                    continue_capturing = false;
                    //To stop capturing the packets close the socket
                    mainSocket.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "MJsniffer", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

 //Start receiving the packets asynchronously
                    mainSocket.BeginReceive(byte_data, 0, byte_data.Length, SocketFlags.None,
                        new AsyncCallback(OnReceive), null);

 //Start receiving the packets asynchronously
                    mainSocket.BeginReceive(byte_data, 0, byte_data.Length, SocketFlags.None,
                        new AsyncCallback(OnReceive), null);

 switch (ipHeader.ProtocolType)
            {
                case Protocol.TCP:

                    TCPHeader tcpHeader = new TCPHeader(ipHeader.Data,    //IPHeader.Data stores the data being carried by the IP datagram
                                                        ipHeader.MessageLength);  //Length of the data field                    

                    TreeNode tcpNode = MakeTCPTreeNode(tcpHeader);

                    rootNode.Nodes.Add(tcpNode);

                    //If the port is equal to 53 then the underlying protocol is DNS
                    //Note: DNS can use either TCP or UDP thats why the check is done twice
                    if (tcpHeader.DestinationPort == "53" || tcpHeader.SourcePort == "53")
                    {
                        TreeNode dnsNode = MakeDNSTreeNode(tcpHeader.Data, (int)tcpHeader.MessageLength);
                        rootNode.Nodes.Add(dnsNode);
                    }

                    break;

                case Protocol.UDP:

                    UDPHeader udpHeader = new UDPHeader(ipHeader.Data,              //IPHeader.Data stores the data being 
                        //carried by the IP datagram
                                                       (int)ipHeader.MessageLength);//Length of the data field                    

                    TreeNode udpNode = MakeUDPTreeNode(udpHeader);

                    rootNode.Nodes.Add(udpNode);

                    //If the port is equal to 53 then the underlying protocol is DNS
                    //Note: DNS can use either TCP or UDP thats why the check is done twice
                    if (udpHeader.DestinationPort == "53" || udpHeader.SourcePort == "53")
                    {

                        TreeNode dnsNode = MakeDNSTreeNode(udpHeader.Data,
                            //Length of UDP header is always eight bytes so we subtract that out of the total 
                            //length to find the length of the data
                                                           Convert.ToInt32(udpHeader.Length) - 8);
                        rootNode.Nodes.Add(dnsNode);
                    }

                    break;

                case Protocol.Unknown:
                    break;
            }

mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.IP); 

MODEM_SendString("AT+UNSOLICITEDTX=128,0,");
MODEM_SendInt(flashParam.channel);
MODEM_SendString(",1,2,1,78,0,FF:FF:FF:FF:FF:FF,01:0C:CC:00:00:00,61:2f:68:00:00:02\r");