There was a time before NAT, where every machine had a publicly routable IP, and things were good. Any machine could talk directly to any port on any other machine (firewall willing). Until one day, IP exhaustion attacked.
Thankfully NAT doesn't exist in IPv6, because 2^128 addresses should be enough for everybody.
Thankfully NAT doesn't exist in IPv6, because 2^128 addresses should be enough for everybody.