There's so many address' that there's no need for NAT'ing unless it's for security reasons. To out it in perspective my company currently has 512 public ipv4 address. We have recently received our ipv6 allocation and (I'm on the train so can't remember the exact number) We've got north or a trillion trillion IP address' with that many ips we can have one for every server. So there's no need to use the private space ipv4 address. Each server can have its own public IP address'.