The answer is to check the firewall policies that reference the VPN interface. Even when a VPN tunnel is up and Phase 2 settings correctly define local and remote subnets, traffic will not pass unless a firewall policy explicitly permits it on the FortiGate. This is because the tunnel interface acts as a logical ingress and egress point; without a policy allowing traffic from the source zone to the VPN zone (or vice versa), the traffic is dropped by the implicit deny rule. On the Fortinet NSE 7 Advanced Security NSE7 exam, this scenario tests your understanding that a tunnel’s control plane (IKE/IPsec) can be fully established while the data plane remains blocked by missing or misconfigured policies—a common trap where candidates focus only on Phase 2 selectors. Remember the memory tip: “Tunnel up, traffic stuck? Check the policy truck.”
NSE7 Troubleshooting and Diagnostics Practice Question
This NSE7 practice question tests your understanding of troubleshooting and diagnostics. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A FortiGate administrator is troubleshooting a VPN tunnel that connects to a remote site. The tunnel is up, but traffic is not passing. The administrator checks the Phase 2 settings and sees that the local and remote subnets are correctly defined. What is the next step to diagnose the issue?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check the firewall policies that reference the VPN interface
Option A is correct. Missing or incorrect firewall policies are a common cause of traffic not passing through an established VPN.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Check the firewall policies that reference the VPN interface
Why this is correct
Even if the tunnel is up, traffic must be allowed by a firewall policy from the VPN interface to the destination zone.
Routing is typically handled by the tunnel interface; if the tunnel is up, routes are usually present.
✗
Run 'diagnose vpn ike log' to check for Phase 1 errors
Why it's wrong here
Phase 1 is already up; this would not reveal traffic forwarding issues.
✗
Restart the VPN tunnel
Why it's wrong here
Restarting would not resolve missing policies.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE7 subnetting questions on CIDR, address ranges, and subnet selection.
Troubleshooting and Diagnostics — This question tests Troubleshooting and Diagnostics — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Check the firewall policies that reference the VPN interface — Option A is correct. Missing or incorrect firewall policies are a common cause of traffic not passing through an established VPN.
What should I do if I get this NSE7 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related NSE7 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.