Yes you do, however, most MP games do not work due to a long and consistent bug. WTJ, short for "Waiting to join" it is a notorious infection that seeps into the UDP packets and causes all the electrons to mutate into fat over sized packets. Then craming into your internet pipe and DDosing your server! So many have losts their games to this herecy.
No but really all joked aside you really do need to port forward. The problem MP is bugged right now. Most if not all MP games wont work because of the waiting to join bug. The host needs to port forward TCP/UDP 2303.
Do not fret however, there is a mod called Project Apex that fixes the waiting to join bug, and adds many other cool features to MP games. Hockeykid is working on it. You should check it out
