Do you need to create Bi-Directional rules? Lets just say you want to allow DNS port 53 from LAN to LAN2. Do you also need to create a rule for LAN2 to LAN on the same port so that the traffic can flow both ways? Is there certain cases where you need to do this and others you dont? This is v8.3.0.
You do not need bi-directional rules. The firewall is stateful. If a packet goes from LAN to LAN2 the return traffic will come back from LAN2 to LAN and match this current session (provided the packet comes back within the idle timeout configured for this service).