IPHostEntry

using System;// j ava2 s  .  c  om
using System.Net;

class MainClass
{
   public static void Main(string[] argv)
   {
      IPAddress test = IPAddress.Parse("64.200.123.1");

      IPHostEntry iphe = Dns.GetHostByAddress(test);

      foreach(string alias in iphe.Aliases)
      {
         Console.WriteLine("Alias: {0}", alias);
      }
   }
}

using System;// j  av a  2s  .  c  o  m
using System.Net;

class MainClass
{
   public static void Main(string[] argv)
   {
      IPAddress test = IPAddress.Parse("64.200.123.1");

      IPHostEntry iphe = Dns.GetHostByAddress(test);

      foreach(IPAddress address in iphe.AddressList)
      {
         Console.WriteLine("Address: {0}", address.ToString());
      }
   }
}

using System;//java2s  .c  o  m
using System.Net;

class MainClass
{
   public static void Main(string[] argv)
   {
      IPHostEntry results = Dns.GetHostByName("www.java2s.com");

      Console.WriteLine("Host name: {0}",results.HostName);

      foreach(string alias in results.Aliases)
      {
         Console.WriteLine("Alias: {0}", alias);
      }
      foreach(IPAddress address in results.AddressList)
      {
         Console.WriteLine("Address: {0}",
                     address.ToString());
      }
   }
}