NSE7 Advanced VPN and Zero Trust Practice Question
You run 'diagnose vpn ike gateway list' on a FortiGate hub and see the following output for a spoke connection: IKE SA state: ESTABLISHED, IPsec SA state: UP, but the spoke cannot route traffic to other spokes. The ADVPN shortcut tunnel is not being established. What is the MOST likely cause?
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
✓
The hub has a static route for the spoke subnet pointing to the tunnel interface
In ADVPN, the hub must not include static routes for the spoke subnets, otherwise the spokes will use the hub as next-hop and not attempt shortcut establishment. The hub should use dynamic routing (BGP/OSPF) to propagate routes but not install a route with a next-hop of the hub itself for other spoke subnets. Option B is correct.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DPD is not configured on the hub
Why it's wrong here
DPD is for dead peer detection, not directly related to shortcut establishment.
- ✓
The hub has a static route for the spoke subnet pointing to the tunnel interface
Why this is correct
When the hub has a static route for a spoke subnet, it becomes the next hop for traffic between spokes, preventing shortcut establishment. ADVPN requires the hub to not have static routes for spoke subnets; it should rely on dynamic routing to propagate routes but not as a next-hop.
- ✗
The spoke's phase2 proposal does not match the hub's proposal
Why it's wrong here
If IPsec SA is UP, the phase2 proposals match. So this is not the cause.
- ✗
The spoke is using a different IKE version than the hub
Why it's wrong here
If IKE SA is established, the IKE version matches.
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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.