Important Multi-player connecting requirement please.
Posting here from what was posted on steam to be sure its addressed.
Please add the ability for fixed source port or fixed source range for RFC 3489 or RFC 5389 for players to connect to one another.
The reason for this is and as it is its fully dynamic which means your source port can be from 49152 to 65535 making firewalling that might be a transparent firewall impossible and the problem can get worse the more I try to explain so I'm going to make this simple in what happens. However note that you can have someone use fixed source port and fixed source range and someone with fully dynamic and this works fine with a firewall setup on fixed source port or fixed source port range.
When you start a Multi-player you and another player send your source port thats fully dynamic to the server and the server sends your source port to the other player.
The players from their source port (P1 = 49300 P2 = 56000) then tries to connect to the other players source port so.
P1 Source port 49300 > P2 Remote port 56000
P2 Source port 56000 > P1 Remote port 49300
In a open firewall setup where it allows all the first attempt likely will not work until the firewall make a state on the first attempt. But you can't firewall this on a transparent firewall because you don't know what the ports are going to be until it happens.
With one wanting to firewall with fixed source port or fixed source range and another player wanting fully dynamic heres how that works
lets say its a fixed source range the game might sent traffic on one of your given fixed source range ports say 60000-60010 and the game picks one thats not in use on your system say 60000 for P1 and P2 has a fully dynamic port say 52001. you can now firewall in UDP ports 60000-60010 for each other to connect without allowing all UDP ports.
P1 Source port 60000 > P2 Remote port 52001
P2 Source port 52001 > P1 Remote port 60000