title: Message: Undefined index: REMOTE_HOST in $_SERVER
body: <p>Why do I get this error when I try to retrieve host name of remote user ?</p>
  
  <pre><code>Message: Undefined index: REMOTE_HOST
  </code></pre>
  
  <p>When reading documentation I came to know that it needs to be enabled in httpd.conf. But I am not sure what needs to be edited in httpd.conf.</p>