An existing connection was forcibly closed by the remote host

protected void Page_Load(object sender, EventArgs e)
        {
            byte[] data = new byte[1024];
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.0.109"), 10006);

            Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            string welcome = "Hello";
            data = Encoding.ASCII.GetBytes(welcome);
            server.SendTo(data, data.Length, SocketFlags.None, ip);

            IPEndPoint sender11 = new IPEndPoint(IPAddress.Parse("192.168.0.109"), 10009);
           // IPEndPoint sender11 = (IPEndPoint)ClientID
            EndPoint tmpRemote = (EndPoint)sender11;



            data = new byte[1024];
            int receivedDataLength = server.ReceiveFrom(data, ref tmpRemote);

            Response.Write(tmpRemote.ToString());
            Response.Write(Encoding.ASCII.GetString(data, 0, receivedDataLength));