This NSE7 practice question tests your understanding of advanced vpn and zero trust. 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.
An administrator is troubleshooting an IPsec VPN tunnel between two FortiGates. The tunnel is up, but traffic is not passing. The administrator runs 'diagnose vpn tunnel list' and sees that both phase 1 and phase 2 are up. The policy allows traffic from both sides. What should the administrator check next?
Check the routing table for routes to the remote subnet
Routes are needed to send traffic into the tunnel.
Increase the phase 2 keylife
Why wrong: Keylife does not affect traffic flow.
Check the FortiGate's NTP status
Why wrong: NTP is not directly related to traffic flow.
Disable DPD
Why wrong: DPD affects tunnel liveliness, but tunnel is up.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Check the routing table for routes to the remote subnet
Since both phases are up and policies are correct, the issue is likely routing. The administrator should verify that the correct routes are pointing to the VPN interface (tunnel interface) on both sides. Without proper routes, traffic will not be forwarded into the tunnel.
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
For each option: why learners choose it and why it is or isn't the right answer here.
Check the routing table for routes to the remote subnet
Why this is correct
Routes are needed to send traffic into the tunnel.
Related concept
CIDR notation defines the prefix length.
Increase the phase 2 keylife
Why it's wrong here
Keylife does not affect traffic flow.
Check the FortiGate's NTP status
Why it's wrong here
NTP is not directly related to traffic flow.
Disable DPD
Why it's wrong here
DPD affects tunnel liveliness, but tunnel is up.
Common exam traps
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
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.
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
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
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.
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FAQ
Advanced VPN and Zero Trust — This question tests Advanced VPN and Zero Trust — CIDR notation defines the prefix length..
The correct answer is: Check the routing table for routes to the remote subnet — Since both phases are up and policies are correct, the issue is likely routing. The administrator should verify that the correct routes are pointing to the VPN interface (tunnel interface) on both sides. Without proper routes, traffic will not be forwarded into the tunnel.
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.
CIDR notation defines the prefix length.
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Last reviewed: Jun 21, 2026
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.
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