public static void DoGetHostEntry(IPAddress address)
{
    IPHostEntry host = Dns.GetHostEntry(address);

    Console.WriteLine($"GetHostEntry({address}) returns HostName: {host.HostName}");
}

public static void DoGetHostEntry(string hostname)
{
    IPHostEntry host = Dns.GetHostEntry(hostname);

    Console.WriteLine($"GetHostEntry({hostname}) returns:");

    foreach (IPAddress address in host.AddressList)
    {
        Console.WriteLine($"    {address}");
    }
}

//引入命名空间
using System;
using System.Net;

class MainClass
{
    public static void Main(string[] args) 
    {
        foreach (string comp in args) 
        {
            try
            {
                IPAddress[] addresses = Dns.GetHostEntry(comp).AddressList;

                foreach (IPAddress address in addresses)
                {
                    Console.WriteLine("{0} = {1} ({2})", 
                        comp, address, address.AddressFamily);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("{0} = Error ({1})", comp, ex.Message);
            }
        }
    }
}