title: Is it possible that REMOTE_ADDR could be blank?
body: <p>As far as I'm aware, the webserver (Apache/Nginx) provides the (<code>$_SERVER['REMOTE_ADDR']</code>) based on the claimed location of the requesting user agent. So I understand they can be lying, but is it possible that this value could be blank? Would the network interface or webserver even accept a request without a correctly formed IP?</p>
  
  <p><a href="http://php.net/manual/en/reserved.variables.server.php" rel="nofollow">http://php.net/manual/en/reserved.variables.server.php</a></p>