[TriLUG] Router question: What's the feature called, in which a router port-forwards LAN traffic as if it were WAN traffic

[David Burton via TriLUG]

Here's another router question:  What do you call the feature that I'm
about to try to describe?

Suppose you have a web server on your LAN, at some static IP address (say
192.168.2.99), and your modem is on a public IP address, say 98.97.96.95,
and you configure port forwarding so that incoming WAN (Internet) traffic
to ports 80 and 443 is NAT'd and forwarded to those ports on your web
server.
With *some* routers, if another machine on your LAN tries to access
98.97.96.95:80, it will work: the router will forward the traffic to your
web server at 192.168.2.99, just as it would forward traffic from the
outside world.
But with *other* routers, it doesn't work: from other machines on the LAN
you can only access the web server at its LAN address (192.168.2.99).

What is that feature called, in which the router forwards LAN traffic as if
it were WAN traffic?

Related question:  Which low-end router(s), these days, support IPv6,
client isolation, gigabit ethernet, and the above unknown-name feature?

Note: my current TP-Link TL-WR1043ND does support the unknown-name feature
(but doesn't support client isolation).  My previous router (I've forgotten
the model) did not support the unknown-name feature.