NSE7 Advanced VPN and Zero Trust Practice Question
An administrator configures BGP over an IPsec VPN between two FortiGates. The BGP session is established, but routes from the remote site are not being installed in the local routing table. The admin verifies that the BGP neighbor configuration is correct and the remote site is advertising routes. 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
✓
A firewall policy is blocking BGP traffic on the VPN interface
BGP routes must be allowed by a firewall policy on the loopback or interface used for BGP. Even if the VPN tunnel is up, BGP traffic (TCP port 179) may be blocked by the local-in policy or by the VPN interface's firewall policy if not explicitly allowed.
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 BGP timers are too aggressive causing route flapping
Why it's wrong here
If the session is established, timers are not preventing route installation.
- ✗
The BGP network statement is missing on the local FortiGate
Why it's wrong here
The network statement is needed to advertise routes, not to receive them.
- ✓
A firewall policy is blocking BGP traffic on the VPN interface
Why this is correct
The VPN interface or loopback used for BGP peering must have a firewall policy allowing inbound BGP traffic (TCP 179). Without it, BGP packets are dropped even though the VPN tunnel is up.
- ✗
The next-hop IP address is not reachable
Why it's wrong here
If BGP session is established, the next-hop should be reachable; this would cause a different symptom like BGP session flapping.
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.