Symfony2: app_dev.php allow access only to IP address

config

$whitelistIPs = array('127.0.0.1', 'fe80::1', '::1', 'my.organisation.ip.address');

//allow app_dev.php only under these conditions (prevent for production environment) uses HTTP_X_FORWARDED_FOR because behind load balancer
if (
    isset($_SERVER['HTTP_X_FORWARDED_FOR']) &&
    ( ! in_array(@$_SERVER['HTTP_X_FORWARDED_FOR'], $whitelistIPs) )
){
    header('HTTP/1.0 403 Forbidden');
    exit('You are not allowed to access the development environment.');
}