NAT's & firewalls are completely different!
Firewalls are for security. NAT's are not.
NAT is needed to connect multiple networked units through a single internet connection where only a single IP address has been provided ... or a similar scenario where many networkable units require connection through a significantly reduced number of connection points.
Just a quick note that at home, I have two laptops, one desktop PC, one server PC, two iphones (via wifi), one Wii, one PS3, one network enabled HDTV, one networked Bluray player (not PS3) and one HD movie box ... and that's 11 IP address right there .... what's that rumour I keep hearing about IPV4 addresses running out?
Moving to IPV6 sounds like a great idea .. but once again ... why would you have hundreds/thousands/millions/billions of external IP addresses assigned, when you really only need one or even several IP presences to the rest of the world.
If every single unit has it's own external IP, it's fully addressable by the rest of the world, and hence accessible to the rest of the world.
Network Address Translation is here to stay, and so it should be.
I wouldn't even know where to start in installing a firewall on my Wii :p
