title: Abuse of PHP function checkdnsrr
body: <p>I have a php page which uses the PHP function <code>checkdnsrr</code> repeatedly.</p>
  
  <p>Are their any limits on how many times I can use it in a day/hour/month etc before being banned?</p>
  
  <p>Could my server IP be banned for using it too much?
  Are their any other things that could happen if I use it too much?</p>