C#查询Whois代码

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net;
using System.Net.Sockets;
using System.Text;
public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string _r = Whois(TextBox1.Text.Trim());
        
        Response.Write(_r.Replace("\r\n","<br>"));
    }

    /**//// <summary>
    /// 域名注册查询
    /// </summary>
    /// <param name="domain">输入域名，不包含www</param>
    /// <returns></returns>
    public static string Whois(string domain)
    {
        if (domain == null)
            throw new ArgumentNullException();
        int ccStart = domain.LastIndexOf(".");
        if (ccStart < 0 || ccStart == domain.Length)
            throw new ArgumentException();
        string ret = "";
        Socket s = null;
        try
        {
            string cc = domain.Substring(ccStart + 1);
            s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            s.Connect(new IPEndPoint(Dns.Resolve(cc + ".whois-servers.net").AddressList[0], 43));
            s.Send(Encoding.ASCII.GetBytes(domain + "\r\n"));
            byte[] buffer = new byte[1024];
            int recv = s.Receive(buffer);
            while (recv > 0)
            {
                ret += Encoding.ASCII.GetString(buffer, 0, recv);
                recv = s.Receive(buffer);
            }
            s.Shutdown(SocketShutdown.Both);
        }
        catch
        {
            throw new SocketException();
        }
        finally
        {
            if (s != null)
                s.Close();
        }
        return ret;
    }
}