protected function isValidDomainName($domain_name) {
		return (preg_match('/^([a-z\d](-*[a-z\d])*)(\.([a-z\d](-*[a-z\d])*))*$/i', $domain_name) //valid chars check
			&& preg_match('/^.{1,253}$/', $domain_name) //overall length check
			&& preg_match('/^[^\.]{1,63}(\.[^\.]{1,63})*$/', $domain_name)   ) //length of each label
			&& count(explode('.', $domain_name))>1;
	}