protected function validateActiveUrl( $attribute, $value )
	{
		if ( !is_string( $value ) )
		{
			return false;
		}

		if ( $url = parse_url( $value, PHP_URL_HOST ) )
		{
			return count( dns_get_record( $url, DNS_A | DNS_AAAA ) ) > 0;
		}

		return false;
	}