vista下，UdpClient.Receive接收失效，xp下正常

        C# 客户端接收：
        private readonly IPAddress GroupAddress = IPAddress.Parse("255.255.255.255");
        private readonly int GroupPort = 8088;
        private static ActionListening uniqueInstance = new ActionListening();
        private UdpClient listener;
        public void Class1()
        {           
            Thread thread = new Thread(new ThreadStart(StartListener));                        
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
        }        public void StartListener()
        {            
            bool done = false;
            try
            {
                if (listener == null)
                {
                    listener = new UdpClient(GroupPort);
                }
                IPEndPoint groupEP = new IPEndPoint(GroupAddress, 11000);                while (!done)
                {
                    byte[] bytes = listener.Receive(ref groupEP);                    string resStr = Encoding.ASCII.GetString(bytes, 0, bytes.Length);
                }
            }
            catch (Exception e)
            {
                
            }
            finally
            {
                listener.Close();
            }        } Java服务器发送：
        private boolean sendMessageToClient(String[] computerName,
     String messageContent, int portNumber)
        {
            String methodName = "sendMessageToClient()";
            DatagramSocket socket = null;
            String machineName = null;
            try
            {
                // generate buffer
                byte[] buf = messageContent.getBytes();
                // generate DatagramSocket instance
                socket = new DatagramSocket();
                int size = computerName.length;
                for (int i = 0; i < size; i++)
                {
                    try
                    {
                        machineName = computerName[i];
                        InetAddress address = InetAddress.getByName(computerName[i]);                        DatagramPacket packet = new DatagramPacket(buf, buf.length,
                            address, portNumber);
                        socket.send(packet);
                    }
                    catch (UnknownHostException e)
                    {                    }
                }
            }
            catch (IOException e)
            {
                return false;
            }
            catch (Exception e)
            {
                return false;
            }
            finally
            {
                try
                {
                    if (socket != null)
                    {
                        socket.close();
                    }
                }
                catch (Exception e)
                {
                    return false;
                }
            }
            return true;
        }
    }大概就是这个样子，在XP下反应很快，及时收到，但在vista下就收不到了，请问有朋友教我吗