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

[Michael Marley via TriLUG]

On 10/13/18 11:23 AM, David Burton via TriLUG wrote:

> 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.

That feature is called Hairpin NAT
(https://en.wikipedia.org/wiki/Hairpinning).  As far as which routers
support all those features, I would highly recommend looking at OpenWRT,
which runs on many routers (including yours, I think), is updated much
more regularly and for much longer than most vendor firmwares, and
supports all those features.

Michael