11. Other essential firewall functions

11.1 Address translation (NAT)

NAT address translation enables terminals on the private network to interact with terminals on the public network, in which case the private network is privately addressed. NAT enables IP addresses to be translated in both directions: private addresses into public addresses, and public addresses into private addresses. NAT makes it possible to artificially increase the number of IP addresses available on the public network, thus addressing the delicate problem of the shortage of IPv4 public addresses. Private addresses that only make sense within a private network can be reassigned from one private network to another, thus increasing...