Also note that even with a proxy or firewall you will only be hiding your internal network ip's but your external IP provided by your DLS / Cable provider can always be found. In a proxy world you are in essence taking your local IP (10.1.1.1) and converting it to a valid internet IP (65.2.45.1) which can always be identified. You can however spoof yourself when are scanning other networks, but most people turn on anti-spoofing so it drops the packets anyway.