Two devices that we (and the associated external companies) want to be able to access over the internet, helpfully both using port 80 among others, without exposing our corporate network to whatever ...
Regarding bridge mode e.g. one has a router-modem(as in 'home router' so it does NAT too and also a modem inside), and a router(i.e. a 'home/NAT router' with no modem), and one wants to connect them.