NSE7 Troubleshooting and Diagnostics Practice Question
A FortiGate is configured with a VIP for an internal web server. Users report that the web server is unreachable from the internet, but it is accessible from the internal network. The administrator runs 'diagnose debug flow' with filters for the public IP and sees that the traffic reaches the FortiGate but is dropped with the message 'iprope_in_check() check failed, drop'. What is the MOST likely cause?
⚠ Common exam trap
The trap here is focusing on NAT or routing when the debug message clearly points to a policy lookup failure.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A firewall policy allowing traffic from the internet to the VIP is missing or misordered.
The debug flow message 'iprope_in_check() check failed, drop' indicates that the incoming packet did not match any firewall policy. For a VIP, a policy must explicitly permit traffic from the external interface to the VIP. If such a policy is absent, disabled, or ordered after a deny policy, the packet is dropped. Internal access works because it uses a different policy path, which is why the issue is isolated to external users.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The VIP is not configured with the correct external interface.
Why it's wrong here
If the VIP were bound to the wrong external interface, traffic would not match the VIP at all, and the debug flow would not show a drop at iprope_in_check. Instead, the packet might be dropped earlier or not match any policy. The specific drop message indicates that the packet reached the policy check but failed due to policy or routing issues, not VIP interface binding.
- ✗
The web server's default gateway is not set to the FortiGate's internal interface.
Why it's wrong here
If the server's default gateway were incorrect, return traffic from the server would not reach the FortiGate, causing asymmetric routing or no response. However, the debug flow shows the incoming packet being dropped at iprope_in_check, meaning the drop occurs before the packet is forwarded to the server. Thus, the server's gateway is not the cause of this specific drop.
- ✓
A firewall policy allowing traffic from the internet to the VIP is missing or misordered.
Why this is correct
The iprope_in_check failure typically indicates that no firewall policy matched the incoming traffic. For a VIP, a policy must explicitly allow traffic from the external interface to the VIP. If the policy is missing, disabled, or placed after a deny policy, the packet is dropped. This matches the symptom: internal access works because it uses a different policy path.
- ✗
The VIP is configured with port forwarding, but the external port does not match the service port.
Why it's wrong here
If port forwarding were misconfigured, the packet would still match the VIP and proceed to policy check, but the destination port translation might fail later. The iprope_in_check drop occurs before any NAT translation, during policy lookup. So a port mismatch would not produce this specific drop message; it would likely result in a different error or a connection timeout.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Fortinet exam blueprint
This NSE7 practice question is part of Courseiva's free Fortinet certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the NSE7 exam.