Exam NSE7_FSN_AR-7.6 Topic 1 Question 121 Discussion

The correct answers are A, D, and E . This is a feasible path RPF check scenario. In FortiGate's default RPF behavior, FortiGate checks whether the routing table contains a valid return route to the source IP address through the same interface on which the packet arrived . The study guide's RPF feasible path example states that FortiGate "checks the routing table for a route that matches the source address and incoming interface of the first original packet." It then gives the exact result: User A passes because "there is a default route through wan1," so packets received on wan1 pass the RPF check regardless of source address.
User B fails because FortiGate does not have a route to 95.56.234.24 through wan2 . User C fails because FortiGate does not have a route to 10.0.4.63 through port1 . Therefore, option B is wrong because FortiGate is not allowing asymmetric return routing here. Option C is wrong because the default route points out wan1 , not port1 , so it cannot validate User C's packet arriving on port1.