No, you don't need to configure your IPv4 or IPv6 .
If you and your friend can't see each-other's server then there maybe some connection problems, you can find troubleshooting guide here: Troubleshooting#Can.27t_find-join-host_a_game .
You can always get all your friends to play the game with you using Tunngle . And you can also use the social sites and other gaming forums to let more people know about your game and Tunngle .
By doing that you should start getting more players .