JNCIS-ENT Tunnels Practice Question
You need to configure a GRE tunnel that requires routing multiple distinct customer VRFs over a single GRE transport link. Which feature should you combine with the GRE tunnel interface?
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
✓
Multiprotocol BGP (MP-BGP) running over the GRE interface with VPN inet-vpn unicast family.
To transport multiple VRFs across a single tunnel interface, BGP or another routing protocol running over the tunnel must exchange VPN-IPv4/VPN-IPv6 routes, or Logical Systems / Multiprotocol BGP can be utilized.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Static routes pointing directly to each customer default gateway.
Why it's wrong here
Static routes do not scale for carrying multiple isolated VRFs across a single interface without heavy overhead.
- ✗
Enabling native VLAN tagging on the gr-0/0/0 unit 0 interface.
Why it's wrong here
GRE tunnel units in Junos do not support native 802.1Q VLAN subinterfaces directly in the same manner as physical Ethernet interfaces.
- ✓
Multiprotocol BGP (MP-BGP) running over the GRE interface with VPN inet-vpn unicast family.
Why this is correct
MP-BGP with VPN-IPv4/IPv6 families allows carrying multiple VRF routing tables across a single layer 3 tunnel link.
- ✗
Layer 2 bridging configuration under the gr- interface.
Why it's wrong here
gr- interfaces are layer 3 interfaces and do not support direct layer 2 bridging.
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.
About these practice questions
One of 506 original JNCIS-ENT practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIS-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIS-ENT exam.