- return 0 === substr_compare(sprintf('%032b', ip2long($requestIp)), sprintf('%032b', ip2long($address)), 0, $netmask);
+ if (false === ip2long($address)) {
+ return self::$checkedIps[$cacheKey] = false;
+ }
+
+ return self::$checkedIps[$cacheKey] = 0 === substr_compare(sprintf('%032b', ip2long($requestIp)), sprintf('%032b', ip2long($address)), 0, $netmask);