UDP packet Sent once but received thrice

Question

Hi,

I am writing a simple code to send and receive data on a udp socket.

the code works ok except for the data is getting received thrice .

I am new to this so please bare with me... :)

<<<<<<<<<<<<<<<<<<<sender code>>>>>>>>>>>>>>>>>>>

            Socket server = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, 

ProtocolType.Udp);

            server.EnableBroadcast = false;

            server.ExclusiveAddressUse = false;

            IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);

            

            byte[] data = Encoding.ASCII.GetBytes(textBox1.Text.Trim());

            server.SendTo(data, iep);

            

            server.Close();

<<<<<<<<<<<<<<<<<Receiver code>>>>>>>>>>>>>>>

 private void OnReceive(IAsyncResult ar)

        {

            try

            {

                UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;

                IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;

                UdpState s = new UdpState();

                s.e = e;

                s.u = u;

                Byte[] receiveBytes = u.EndReceive(ar,ref e);

                string receiveString = Encoding.ASCII.GetString(receiveBytes);

                s.e = e;

                listBox1.Items.Add("Received:" + receiveString+e.Address.ToString());

                u.BeginReceive(new AsyncCallback(OnReceive), s);

                

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            CheckForIllegalCrossThreadCalls = false;//Will remove later

        }

        private void StartReceive_Click(object sender, EventArgs eA)

        {

            IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);

            IPEndPoint e = new IPEndPoint(IPAddress.Any, 9050);

            UdpClient u = new UdpClient(e);

            u.Client.Blocking = false;

            UdpState s = new UdpState();

            s.e = e;

            s.u = u;

            s.u.Client.DontFragment = true;

            s.u.Client.Ttl = 1;

            listBox1.Items.Add("listening for messages");

            u.JoinMulticastGroup( IPAddress.Parse("224.100.0.1"));

            u.BeginReceive(new AsyncCallback(OnReceive), s);

        }

    public class UdpState

    {

        public IPEndPoint e;

        public UdpClient u;

    }