c# - C# SharpPCap Syn スキャン

Question

SharpPcap を使用して TCP SYN スキャンを実行しようとしています。WireShark を使用して、パケットが NIC から送信されるかどうかを確認していますが、送信されますが、応答がありません。 NMAPドキュメンテーションには、SYN|ACK または RST TCP パケットを取得する必要があると書かれていますが、何も取得せず、他のステーションが起動しており、それらの間で telnet を実行すると、wireshark で tcp ハンドシェイクが正常に表示されます。

コードは次のとおりです。

            //Generate a random packet
            EthernetPacket packet = EthernetPacket.RandomPacket();
            packet.SourceHwAddress = srcMacAddress;
            packet.DestinationHwAddress = dstMacAddress;

            string ss = "Message TCP";
            byte[] bArray = System.Text.Encoding.ASCII.GetBytes(ss);
            byte[] asd = new byte[60];
            bArray.CopyTo(asd, 20);

            ByteArraySegment bas = new ByteArraySegment(asd);
            TcpPacket tcpPacket = new TcpPacket(bas);

            IpPacket ipPacket = IpPacket.RandomPacket(IpVersion.IPv4);
            ipPacket.TimeToLive = 20;
            ipPacket.Protocol = IPProtocolType.TCP;
            ipPacket.Version = IpVersion.IPv4;
            ipPacket.DestinationAddress = dstIpAddress;
            ipPacket.SourceAddress = srcIpAddress;
            ipPacket.PayloadPacket = tcpPacket; 
            packet.PayloadPacket = ipPacket;
            ipPacket.ParentPacket = packet;

            tcpPacket.ParentPacket = ipPacket;
            tcpPacket.SourcePort = SourcePortNumber;
            tcpPacket.DestinationPort = DestinationPortNumber;
            tcpPacket.Syn = true;
            tcpPacket.WindowSize = 500;
            tcpPacket.AcknowledgmentNumber = 1000;
            tcpPacket.SequenceNumber = 1000;

            tcpPacket.DataOffset = TcpFields.HeaderLength + 1;

            try
            {
                //Send the packet out the network device
                device.SendPacket(packet);
                ScanManager.Instance.AddPacket(packet, IPProtocolType.TCP);
            }
            catch (Exception e)
            {
                Console.WriteLine("-- " + e.Message);
            }

呼び出しコード:

public static bool InitiliazeData(string dstIp)
        {
            bool bResult = false;
            // Print SharpPcap version
            string ver = SharpPcap.Version.VersionString;
            Console.WriteLine("SharpPcap Port scanner\n", ver);

            // Retrieve the device list
            var devices = CaptureDeviceList.Instance;

            // If no devices were found print an error
            if (devices.Count < 1)
            {
                Console.WriteLine("No devices were found on this machine");
                return false;
            }

            Console.WriteLine("The following devices are available on this machine:");
            Console.WriteLine("----------------------------------------------------");
            Console.WriteLine();

            int i = 0;


            foreach (WinPcapDevice dev in devices)
            {
                Console.Out.WriteLine("{0}) {1}", i, dev.Description);
                i++;

                foreach (PcapAddress addr in dev.Addresses)
                {
                    if (addr.Addr != null && addr.Addr.ipAddress != null)
                    {
                        Console.Out.Write("IP: {0}", addr.Addr.ipAddress);


                    }
                }
            }

            Console.WriteLine();
            Console.Write("-- Please choose a device to send a packet on: ");
            i = int.Parse(Console.ReadLine());
            iDeviceNumber = i;
            device = (PcapDevice)devices[i];
            i = 0;
            Console.WriteLine("Ip addresses for the selected interface: ");
            foreach (PcapAddress addr in ((WinPcapDevice)device).Addresses)
            {
                if (addr.Addr != null && addr.Addr.ipAddress != null)
                {
                    Console.Out.Write("{0}) {1}", i, addr.Addr.ipAddress);
                    i++;

                }
            }
            Console.WriteLine();
            Console.Write("-- Please choose a source ip to send a packet from: ");
            i = int.Parse(Console.ReadLine());
            iIpNumber = i;
            int j = 0;
            foreach (PcapAddress addr in ((WinPcapDevice)device).Addresses)
            {
                if (addr.Addr != null && addr.Addr.ipAddress != null)
                {

                    if (j == i)
                    {
                        srcIpAddress = addr.Addr.ipAddress;
                        break;
                    }
                    j++;
                }
            }
            //do
            //{
            //    Console.WriteLine("Please enter the IP that you want to scan: ");
            //    String ipAddressString = Console.ReadLine();
            //    dstIpAddress = IPAddress.Parse(ipAddressString);
            //    if (dstIpAddress != null)
            //        break;
            //    else
            //        Console.Write("Incorrect ip address.");
            //} while (true);

            IPAddress.TryParse(dstIp, out dstIpAddress);
            ARP arpResolver = new ARP(((WinPcapDevice)device));
            dstMacAddress = arpResolver.Resolve(dstIpAddress);
            if (dstMacAddress == null)
            {
                Console.WriteLine("Could not get MAC Address for ip {0}", dstIpAddress);
                return false;
            }
            else
            {
                Console.WriteLine("Destination MAC Address: {0}.", dstMacAddress);
            }
            device.Open();
            srcMacAddress = device.MacAddress;
            device.Close();
            return bResult;
        }