There is one feature available on FortiGate, and I think you should know it, as it modifies a bit what we know about stateful firewalls. In past every packet was treated individually and you had to create policies in both directions. With stateful firewalls we can track connections, and by checking couple of attributes, we can treat them as part of the same session. For example when you initiate connection from a host1 to host2, the returning connection from host2 to host1 will be treated as part of the same connection (session). They have to have the same source/destination and destination/source IPs, port numbers and interfaces.There is an exception from this rule and FortiGate in some specific cases can accept connections on port which was not used in the initial connection. Let me explain how it works on the below example: The host1 has a default gateway on R1 (10.0.1.2), but you may notice that it is not the optimal path to host2 subnet. When we analyze ...