title: How do I retrieve the visitor's ISP through PHP?
body: <p>How do I find out the ISP provider of a person viewing a PHP page?</p>
  
  <p>Is it possible to use PHP to track or reveal it?</p>
  
  <p>If I use something like the following:</p>
  
  <pre><code>gethostbyaddr($_SERVER['REMOTE_ADDR']);
  </code></pre>
  
  <p>it returns my IP address, not my host name or ISP.</p>