NSE7 Advanced VPN and Zero Trust Practice Question
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?
⚠ Common exam trap
NSE7 often tests the assumption that an 'up' tunnel means traffic will flow, ignoring the need for correct routing and policy — candidates may jump to DPD or keylife instead of checking routes.
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
✓
Check the routing table for routes to the remote subnet
If both IPsec phases are up and policies allow traffic, the next most likely issue is missing or incorrect routing. Without a route to the remote subnet pointing to the IPsec tunnel interface, the FortiGate will not send traffic into the tunnel, even though the tunnel is established. Checking the routing table is the logical next step.
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 routing table for routes to the remote subnet
Why this is correct
With both phases up and policies permitting traffic, the failure lies beyond IKE negotiation. FortiGate only forwards traffic into a tunnel when a route to the remote subnet points out the IPsec interface; without it, packets follow the default route instead. Verify the routing table for the correct static or dynamic route.
- ✗
Increase the phase 2 keylife
Why it's wrong here
Phase 2 keylife governs rekeying interval, not whether traffic traverses an established tunnel. Increasing it is tempting because keylife appears in phase 2 settings, and would be correct when rekey failures or SA expiry are disrupting an otherwise working tunnel.
- ✗
Check the FortiGate's NTP status
Why it's wrong here
NTP affects certificate and replay-window timing, but both phases are already established, so clock skew is not blocking traffic now. Checking NTP is tempting because time mismatches break IPsec negotiation, and would be correct when phase 1 or phase 2 fails to come up.
- ✗
Disable DPD
Why it's wrong here
DPD affects tunnel liveliness, but tunnel is up.
Visual reference
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
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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.