Fortinet Fortigate Administrator FCP Fortigate 76 · Free Practice Question Medium
Question 1
Refer to the exhibit.

Which contains a network diagram and routing table output. The Student is unable to access Webserver.
What is the cause of the problem and what is the solution for the problem?
-
A
A. The first packet sent from Student failed the RPF check. This issue can be resolved by adding a static route to 10.0.4.0/24 through wan1.
-
B
B. The first reply packet for Student failed the RPF check. This issue can be resolved by adding a static route to 10.0.4.0/24 through wan1.
-
C
C. The first reply packet for Student failed the RPF check. This issue can be resolved by adding a static route to 203.0.114.24/32 through port3.
-
D
D. The first packet sent from Student failed the RPF check. This issue can be resolved by adding a static route to 203.0.114.24/32 through port3.
Reveal correct answer
Correct answer: C
Explanation
Correct answer: C. The first reply packet for Student failed the RPF check. This issue can be resolved by adding a static route to 203.0.114.24/32 through port3.
Option C is the correct answer based on the provided information, let's analyze it:
Option C states: "The first reply packet for Student failed the RPF check. This issue can be resolved by adding a static route to 203.0.114.24/32 through port3."
The issue is related to the first reply packet from the Student failing the Reverse Path Forwarding (RPF) check and that adding a static route to 203.0.114.24/32 through "port3" will resolve the problem, then you can go ahead with this solution.
In a typical RPF check scenario, it ensures that the incoming packet is arriving on the expected interface based on the routing table. Adding a static route to 203.0.114.24/32 through "port3" may indeed resolve the RPF issue if the routing is misconfigured.
Option C is the correct solution based on your network setup and further analysis, you can proceed with implementing that static route to see if it resolves the issue. Additionally, it's a good practice to monitor the network to ensure that the problem is indeed resolved after making the change.
Extra explanation:
The first reply packet for the Student failed the Reverse Path Forwarding (RPF) check. This issue can be resolved by adding a static route to 203.0.114.24/32 through port3.
Explanation:
Understanding the Network Setup:
The Student (10.0.5.24) is connected to the FortiGate via port3 (10.0.4.254).
The Webserver is located at 203.0.114.24.
The FortiGate has two WAN interfaces:
wan1 (201.0.113.254)
wan2 (203.0.115.254)
The routing table shows:
Directly connected networks: 10.0.4.0/24 (port3), 201.0.113.0/24 (wan1), 203.0.115.0/24 (wan2).
There is no route for 203.0.114.24 via port3.
Issue - Reverse Path Forwarding (RPF) Check Failure:
The Student sends a request to the Webserver (203.0.114.24) via FortiGate.
The Webserver replies, but the reply packet's source is 203.0.114.24, which is not in the routing table through port3.
The FortiGate performs an RPF check to verify if the return path is valid.
Since there is no route for 203.0.114.24 via port3, the packet is dropped due to the RPF check.
Solution:
Add a static route to 203.0.114.24/32 via port3 so that return traffic is correctly routed back to the Student.
Thus, C is the correct answer.
The Reverse Path Forwarding (RPF) check ensures that packets arrive from a valid source based on the routing table. If a packet fails the RPF check, it is dropped.
In this case, the first reply packet from the Webserver to the Student fails the RPF check because the FortiGate does not have a route for 203.0.114.24/32 through port3.
To resolve this, a static route should be added to direct traffic for 203.0.114.24/32 through port3, ensuring proper routing and allowing the Student to access the Webserver.
Discussion
Think the marked answer is wrong, or have a better explanation? Share it below — comments appear after review.
