Symfony\Component\Validator\Constraints\EmailValidator::checkHost PHP Method

Check if one of MX, A or AAAA DNS RR exists.

private checkHost ( string $host ) : boolean
$host	string	Host
return	boolean

    private function checkHost($host)
    {
        return $this->checkMX($host) || (checkdnsrr($host, 'A') || checkdnsrr($host, 'AAAA'));
    }

EmailValidator