Do you need to port forward if you are not behind a router?

[xXFlareXx]

If your computer is directly connected to the router do you have to port forward? If you do please explain what is needed to be done.

[Ad Bot]

[Chrono]

If you are directly connected to the modem, you do not need to port forward.
However being directly connected to the modem is like running DMZ on the router, which exposes your computer on all ports. Make sure you have a good firewall.