protected function validateEmailDNS($field, $value)
    {
        if ($this->validateEmail($field, $value)) {
            $domain = \ltrim(\strstr($value, '@'), '@') . '.';
            if (\defined('INTL_IDNA_VARIANT_UTS46') && \function_exists('\idn_to_ascii')) {
                $domain = \idn_to_ascii($domain, 0, INTL_IDNA_VARIANT_UTS46);
            }

            return \checkdnsrr($domain, 'ANY');
        }

        return false;
    }