C#

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
public class UdpServer
{
    public static void Main()
    {try
        {
            int recv;
            byte[] data = new byte[1024];
            IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);
Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            newsock.Bind(ipep);
            Console.WriteLine("Waiting for a client...");            
            IPEndPoint sender = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);
            EndPoint tmpRemote = (EndPoint)(sender);
            recv = newsock.ReceiveFrom(data, ref tmpRemote);
            Console.WriteLine("Message received from {0}:", tmpRemote.ToString());
            Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
            data = new byte[1024];
            string ss = "Welcome to the Server";
            data = Encoding.ASCII.GetBytes(ss);
            newsock.SendTo(data, data.Length, SocketFlags.None, tmpRemote);
            Console.WriteLine("\nSent Acknowledgement");
           // newsock.Close();           
        }
        catch (Exception e)
        {
            Console.WriteLine("Error..... " + e.StackTrace);
        }
       // Console.ReadLine();      
    }
}

private void Send_Click(object sender, EventArgs e)
       {
           Callback();}
       private void Callback()
       {try
           {
               byte[] data = new byte[1024];
               listBox3.Items.Add("Connecting....");
               IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);
      Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
               listBox3.Items.Add("Connected");
               data = Encoding.ASCII.GetBytes("hello");
               listBox3.Items.Add("Transmitting...");
               server.SendTo(data, data.Length, SocketFlags.None, ipep);//sent hello
               listBox3.Items.Add("Sent...");
     IPEndPoint sender = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);
               EndPoint tmpRemote = (EndPoint)sender;
               listBox3.Items.Add("Message received from {0}:");
               listBox3.Items.Add(tmpRemote.ToString());
               data = new byte[1024];
               int recv = server.ReceiveFrom(data, ref tmpRemote);
               listBox3.Items.Add(Encoding.ASCII.GetString(data,0,recv));
               //listBox3.Items.Add("Stopping client");
               //server.Close();}
           catch (Exception e)
           {
               Console.WriteLine("Error..... " + e.StackTrace);
           }
           Console.ReadLine();}