5 years ago, i remember having this problem, this is the default way to doing it. but the thing is it leaves u Open to anyone who wonts to play some games , "games". You might not be playing a game or not even by your pc and sence u open them ports for all flow traffic. well lets just say dont piss someone off who knows what they are doing
But im not saying this will happin sence you are at a low risk but if someone in your ISP Network Wonts to do some scanning they can pick you up and see you have open active ports.