1. NAT is a way of providing access to the Internet through a single machine that translates the IP addresses. The NAT itself has one or more IP addresses, but all the machines behind the NAT have "private" Internet addresses. Contrast: A NAT provides some firewalling capabilities because isolates the end-nodes while still providing access to the Internet. The isolation is better than packet-filter firewalls, but not as good as proxies. From Hacking-Lexicon