It should work fine as it is. However, while stun servers (default, included ice server) are normally pretty good at making connections through various network configurations, there are exceptions.
If you add your own turn server (not included by default) by using the add ice server multiplayer action, it should more or less garuntee connectivity in all cases.
Note that due to live bandwidth utilization, turn servers are not usually free. I believe there are free ones available with certain usage limitations though.