C# simple smartwhois class

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Diagnostics;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace NWhois
{
    class WhoisClient
    {
        #region privatedata
        #endregion

        #region instance
        public WhoisClient()
        {

        }
        #endregion

        #region properties
        #endregion

        #region methods
        public string Whois(string query, string server = "", int port = 43)
        {
            string srv = server;

            if (string.IsNullOrEmpty(srv))
            {
                srv = getServer(query);
                if (string.IsNullOrEmpty(srv)) return null;
            }

            string result = QuerySrv(query, srv, port);
            string single = getSingle(result, query);
            if (!string.IsNullOrEmpty(single))
            {
                result = QuerySrv(single, srv, port);
                string patt = string.Format("domain name: {0}", query.ToLower());
                int pos = result.ToLower().IndexOf(patt);
                if (pos > 0) {
                    result = result.Substring(pos);
                }

            }
            string hint = getHint(result, "whois server:");
            if (!string.IsNullOrEmpty(hint))
            {
                result = QuerySrv(query, hint, port);
            }
            return result;
        }
        #endregion

        #region privatecode
        private string getServer(string query)
        {
            string buff = QuerySrv(query, "whois.iana.org" , 43);
            if (string.IsNullOrEmpty(buff)) return null;
            string srv = getHint(buff, "whois:");
            return srv;
        }

        private string getHint(string data, string tag)
        {
            string buf = data.ToLower();
            int pos = buf.IndexOf(tag);
            if (pos < 1) return null;
            buf = buf.Substring(pos + tag.Length);
            pos = buf.IndexOf("\n");
            if (pos < 1) return null;
            buf = buf.Substring(0, pos).Trim();
            return buf;
        }

        private string getSingle(string data, string query)
        {
            string buf = data.ToLower();
            int pos = buf.IndexOf("to single out one record");
            if (pos < 1) return null;
            return "=" + query.ToUpper();
        }

        private string QuerySrv(string query, string server, int port = 43)
        {
            string result = null;

            // Console.WriteLine(string.Format("QuerySrv(\"{0}\",\"{1}\",{2})", query, server, port));

            try
            {
                Encoding enc = Encoding.ASCII;
                TcpClient sock = new TcpClient(server, port);
                using (Stream s = sock.GetStream())
                {
                    byte[] qry = enc.GetBytes(query + "\r\n");
                    byte[] buf = new byte[8192];
                    StringBuilder resp = new StringBuilder();
                    s.Write(qry, 0, qry.Length);
                    int nbytes = 0;
                    do
                    {
                        nbytes = s.Read(buf, 0, buf.Length);
                        if (nbytes > 0)
                        {
                            resp.Append(enc.GetString(buf, 0, nbytes));
                        }
                    } while (nbytes > 0);
                    result = resp.ToString();
                }
                sock.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("ERR: QuerySrv(\"{0}\",\"{1}\",{2}) :: {3}", query, server, port, ex.Message));
                result = null;
            }

            return result;
        }
        #endregion

    }
}