- A
The BGP IP addresses are not reachable over the tunnel
Even if the tunnel is up, if the BGP IPs are misconfigured or not routed, BGP won't establish.
- B
IKE version mismatch
Why wrong: Tunnel being up indicates IKE is fine.
- C
The pre-shared key is incorrect
Why wrong: If the pre-shared key were wrong, the tunnel would not be up.
- D
The Cloud Router is not configured
Why wrong: Cloud Router would have been created as part of setup.
Question 131 of 1,000
PCNE Implementing Hybrid Interconnectivity Practice Question
This PCNE practice question tests your understanding of implementing hybrid interconnectivity. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
A company has deployed a Cloud VPN tunnel using route-based VPN (using IKEv2) and has configured BGP on the tunnel. The tunnel is up, but the BGP session is not establishing. What is a 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 BGP IP addresses are not reachable over the tunnel
For route-based VPN tunnels, BGP peering requires that the Cloud VPN gateway and the on-premises router can reach each other's BGP IP addresses. The BGP IPs are typically link-local addresses derived from the tunnel's interface. If the BGP session is not establishing, common issues include incorrect BGP IP configuration, firewall rules blocking BGP (port 179), or the tunnel not passing traffic correctly.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 IP addresses are not reachable over the tunnel
- ✗
IKE version mismatch
Why it's wrong here
Tunnel being up indicates IKE is fine.
- ✗
The pre-shared key is incorrect
Why it's wrong here
If the pre-shared key were wrong, the tunnel would not be up.
- ✗
The Cloud Router is not configured
Why it's wrong here
Cloud Router would have been created as part of setup.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
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.
What to study next
Got this wrong? Here's your next step.
Identify which PCNE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
- →
Implementing Hybrid Interconnectivity — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
Implementing Hybrid Interconnectivity — This question tests Implementing Hybrid Interconnectivity — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The BGP IP addresses are not reachable over the tunnel — For route-based VPN tunnels, BGP peering requires that the Cloud VPN gateway and the on-premises router can reach each other's BGP IP addresses. The BGP IPs are typically link-local addresses derived from the tunnel's interface. If the BGP session is not establishing, common issues include incorrect BGP IP configuration, firewall rules blocking BGP (port 179), or the tunnel not passing traffic correctly.
What should I do if I get this PCNE question wrong?
Identify which PCNE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PCNE practice question is part of Courseiva's free Google Cloud 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 PCNE exam.
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