i just looked the ports up and saw that i made a mistake, here the correction: i opened all ports the game is listening to and these are: 3202 3204 3205 58272 (which is baseport, baseport+2 and baseport+3 and an unknown port never mentioned...)
i´m not sure but if the server has been installed correctly it should be enabled by default. Did the text chat work in the local area? did you open the port for voice chat on the server? (default port+1 and default port+3 should be allowed if i remember correctly) greetings Jörg