Is there really no way for the machine to prevent private ports from being be known without a specific call? It seems to me that machines are designed to follow

Is there really no way for the machine to prevent private ports from being be known without a specific call? It seems to me that machines are designed to follow the standard to be nice and respond back [0]. Even with a whitelist, I have concerns that the machine is opening itself for a DDoS SYN attack by simply replying back rejections. [0] https://secure.wikimedia.org/wikipedia/en/wiki/Port_scan#TCP.2FIP_basic_knowledge https://secure.wikimedia.org/wikipedia/en/wiki/Port_scan#TCP...