string txtResponse = "";
string strResponse = "";

TcpClient tcpWhois = new TcpClient("whois.internic.net", 43);
NetworkStream nsWhois = tcpWhois.GetStream();
BufferedStream bfWhois = new BufferedStream(nsWhois);

StreamWriter swSend = new StreamWriter(bfWhois);
             swSend.WriteLine("google.com");
             swSend.Flush();

StreamReader srReceive = new StreamReader(bfWhois);

while ((strResponse = srReceive.ReadLine()) != null)
{
    txtResponse += strResponse + "\r\n";
}

tcpWhois.Close();

Console.WriteLine(txtResponse);