A long while ago, it was possible to host a server from ingame
without UNPNP, and with.
Currently, regardless of the UNPNP option you choose, on Internet mode,
server cannot be accessed once you host it
and UNPNP always states port forwarding failed.
It's something broken in arma, a consistent issue between everyone.
Arma 3 forums is full of inquires about this, and to no avail
port forwarding set up, doesn't work
DMZ, or whatever sel
nothing helps.
I speak from experience, since I used to host a year ago servers without UNPNP or with as well, no problemo, just to mess around with friends
now it's broken.