using System;

using System.Net;

using System.Threading;

​

public class Program

    {

        public static void Main(string[] args)

        {

            LookupHostName();

            Console.Write("Continue with main thread");

            Thread.Sleep(10000);

        }

​

        private static void LookupHostName()

        {

            object unrelatedObject = "hello";

            Dns.BeginGetHostAddresses("microsoft.com", OnHostNameResolved, unrelatedObject);

        }

​

        private static void OnHostNameResolved(IAsyncResult ar)

        {

            object unrelatedObject = ar.AsyncState;

            IPAddress[] addresses = Dns.EndGetHostAddresses(ar);

​

            foreach (var ip in addresses)

            {

                Console.WriteLine("{0}",ip.Address);

            }

        }

​

    }

​

​