title: Reverse ip, find domain names on ip address
body: <p>How and from where websites like this <a href="http://www.yougetsignal.com/tools/web-sites-on-web-server/">http://www.yougetsignal.com/tools/web-sites-on-web-server/</a> are getting this information from? How can I develop such tool?</p>
  
  <p>Thank you.</p>