Prüfung, ob IP-Adresse eines Users innerhalb der CIDR-Maske

Default_Model_Cidr.php

<?php

class Default_Model_Cidr
{
  public static function match($ip, $range)
		{
		list ($subnet, $bits) = explode('/', $range);
		$ip = ip2long($ip);
		$subnet = ip2long($subnet);
		$mask = -1 << (32 - $bits);
		$subnet &= $mask; 
		$r = ($ip & $mask) == $subnet;
		if(!$r)
			{
				throw new Zend_Exception('Nicht innerhalb des Adressraums', 401);
			}
		return $r;
		}

}

index.php

try
  		{
			Default_Model_Cidr::match($_SERVER['REMOTE_ADDR'], "192.168.71.0/24");
			} catch (Zend_Exception $e)
			{

				$this->redirect('/ausleihe/index/index');
			}