public function checkDns(&$result)
    {
        if ($this->deepWhois && empty($result['regrinfo']['domain']['nserver'])) {
            $ns = @dns_get_record($this->query['query'], DNS_NS);
            if (!is_array($ns)) {
                return;
            }
            $nserver = array();
            foreach ($ns as $row) {
                $nserver[] = $row['target'];
            }
            if (count($nserver) > 0) {
                $result['regrinfo']['domain']['nserver'] = $this->fixNameServer($nserver);
            }
        }
    }