Trying to replicate blocking a games inbound port but leaving the outbound open, but instead of doing it in the windows defender firewall with advanced security, to get it done successfully on router os. Blocking the games inbound only while leaving output alone in defender firewall still allows game connection and no disconnects. Trying it from the router os seems to yield an unwanted result, disconnects, no matter which firewall filter chain is in use, forward, input, output. Tried various combinations of device as src address, dst address, tried doing by interface. Is there any way to replicate the defender firewall inbound only block, while leaving the outbound to do as it pleases so that the game doesn’t disconnect as if it were behaving like the windows defender firewall inbound only block? And is there a good rule to drop faulty packets or is that what the “invalid” flag is for?
The problem when creating firewall rules is that one needs to know exactly what traffic is expected - which combinations of remote_ip/remote_port will be used for connections. For windows defender tash is much easier as it can be configured to allow certain executable to open communiaction ports (any of tehm, not just those defined in advance) and firewall rules adapt automatically.