Well, do you mean QoS for a dedicated that you host ?
or QoS for your game ?
For your own locally hosted dedicated, you are supposed to know the ports that you use
For other servers on which you connect with your game, it's more complicated : most good servers (ie those rent with a real good connection), several dedicated are hosted on the same server, so most of them won't use the default ports.
You can only suppose that most of them will use :
- main game port: 2350 to 2350+100 (udp
and tcp)
- p2p port: 3450 to 3450+100 (tcp)
(and if you want more chances, increase the range to +200 or +300)
Also, by default your game will use local 3450 (tcp) for the p2p (when other players game contact your game p2p), so a lower QoS priority on this one is probably not bad.
Btw, the 1st thing is to check that the configured max upload/download values in your game are below the bandwidth really usable by the game on your connection. Once that is ok you can eventually think about QoS...