alt Hacker News> NAT per se does not prevent an outside host from connecting to a host on your local network.
Yep, and a firewall per se does not prevent an outside host from connecting to a host on your local network. You can bang your head all day long, the side effect of NAT is to only allow incoming traffic that refers to an established connection that was initiated from the local network. How is this different from a firewall that does
Allow established, related
Allow outbound
Deny inbound
No, the side effect of NAT is that outbound connections made from your network look like they come from the router's WAN IP. It doesn't filter incoming traffic.
If it did then you might have a point, but since it doesn't it's very different from a firewall that's configured to do that.