[apeacox]

DNAT. You map one/more ports from your router exposed on internet to ip:port of the local app.

However, http/https ports are already used on routers to offer an admin web GUI. It’s technically possible to circumvent this with some ad-hoc firewall rules, but it depends if the router admin UI let’s you do that.

[gdamjan1]

> However, http/https ports are already used on routers to offer an admin web GUI.

not on the wan side I'd hope

[apeacox]

Exactly, they aren’t exposed outside. That’s why you can “potentially” add rules to route request from the outside to an internal host:port, even 80/143. On the LAN you would still able to connect to router admin.