I have a server, with a combined apache website and sql gaming server on same server. I have the domain being routed to a different nameserver/proxy with ddos protection, and made a seperate subdomain there that goes directly to the game server because it is game traffic and cannot use the services. Everything works fine, but I want to block the incoming subdomain from accessing anything but the game server port on the destination server.
Question: On the game server firewall, how can I only allow the incoming subdomain traffic to use a specific port, and block all other ports? I don't want it to impact the website traffic using the domain name and ports 80/443