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];
          //  bool done = false;
            while (true)
            {
                IPEndPoint ipep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9050);
                Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                // newsock.Bind(ipep);
                newsock.Start();

                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.ReadLine();
                Console.WriteLine("Message received from {0}:", tmpRemote.ToString());
                Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));//hello is received           

                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();
       
    }
}