protected function truncateHost($host)
    {
        $tlds = SimpleUrl::getAllTopLevelDomains();
        if (preg_match('/[a-z\-]+\.(' . $tlds . ')$/i', $host, $matches)) {
            return $matches[0];
        } elseif (preg_match('/[a-z\-]+\.[a-z\-]+\.[a-z\-]+$/i', $host, $matches)) {
            return $matches[0];
        }

        return false;
    }