linux - How to make a pc act as a router on some port

I have a linux server in my lab(hereafter called pc1), and I have a windows pc2 where I have a game server running on. But since it's a private network, and the only pc that the internet can access is the pc1. But I want the game server on pc2 be seen by outside internet. But I have no access permission to the router of our lab. So I want the pc1 to act as some kind of router that forwards pc1:port1 to pc2:port2 and backwards. And then the request from outside internet can access pc2:port2 and reply from pc2 can also reach the outside. Is there any method to achieve this?