/**
* @return bool Whether or not an MX record exists for the
* email address's host name.
*/
protected function checkDNS()
{
$mxRecordExists = checkdnsrr(trim($this->parser->getParsedDomainPart()), 'MX');
if (!$mxRecordExists) {
$this->warnings[] = self::DNSWARN_NO_RECORD;
$this->addTLDWarnings();
}
return $mxRecordExists;
}