Earlier quoted context omitted.
> The nice thing about NAT is open ports on your internal network are hidden to the outside world by default. That is usually not true. NAT punching is a thing for decades now.
- NAT punching does require cooperation of programs on the protected machines, though, no? How is it different from them inviting traffic in any other way (like, requesting a page via https from an infected server could hijack the client on the protected machine if the client has security holes in the right places; the https client is willing to get traffic here, just as some VoIP program is willing to receive a call…
As does listening to a port.
> And is it any different from a stateful firewall on IPv6?
Hum, not much. And that's the point, all of those are basically the same. NAT doesn't give you much security, and NAT without a firewall usually gives you less security than a firewall, since NAT usually is configured for connectivity, and a firewall for protection.