- A
Verify that the VPC's dynamic routing mode is set to 'global' if using regional routing.
Global routing ensures the default route is propagated to all regions.
- B
Check VPC firewall rules to ensure they allow egress traffic from VMs.
Why wrong: Firewall rules are not the cause of routing path selection.
- C
Check the route priority (preference) of the default route learned via BGP compared to the default internet gateway route.
The route with the lowest priority (highest preference) is chosen.
- D
Verify that the Cloud Router is configured to advertise the default route to the VPC.
Cloud Router must be configured to import routes and the VPC must accept them.
- E
Ensure that the on-premises router is sending the default route with a higher local preference.
Why wrong: Local preference affects outbound from GCP to on-premises, not inbound route selection.
Quick Answer
The answer is to verify that the Cloud Router is configured to advertise the default route to the VPC, because the core issue when a default route via VPN is not working in global routing mode often stems from a mismatch in the VPC’s dynamic routing scope. When an on-premises BGP router advertises 0.0.0.0/0, the Cloud Router receives it, but if the VPC uses regional dynamic routing, that default route is only propagated within the single region where the VPN tunnel is attached—leaving VMs in other regions unable to use the VPN for internet egress. On the Google Professional Cloud Network Engineer exam, this scenario tests your understanding of how Cloud Router’s route advertisement interacts with VPC routing modes, and a common trap is assuming a received BGP route is automatically available globally. To remember, think “global for global reach, regional for local only”—if your VPC is in regional mode, the default route stays stuck in one region, so always confirm the dynamic routing mode matches your intended egress scope.
PCNE Implementing hybrid interconnectivity Practice Question
This PCNE practice question tests your understanding of implementing hybrid interconnectivity. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 Cloud VPN with dynamic routing (BGP) is established between an on-premises network and Google Cloud. The on-premises BGP router is advertising a default route (0.0.0.0/0). The Cloud Router in Google Cloud is receiving this route, but network traffic from Google Cloud VMs to the internet is not being routed through the VPN. Which THREE troubleshooting steps should you take? (Choose three.)
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
Verify that the VPC's dynamic routing mode is set to 'global' if using regional routing.
Option A is correct because the VPC's dynamic routing mode determines the scope of route propagation. If the VPC uses regional dynamic routing, Cloud Router only propagates routes within the region where the VPN tunnel is attached. A global dynamic routing mode is required for the BGP-learned default route to be available across all regions, ensuring VMs in any region can use the VPN for internet egress.
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.
- ✓
Verify that the VPC's dynamic routing mode is set to 'global' if using regional routing.
Why this is correct
Global routing ensures the default route is propagated to all regions.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Check VPC firewall rules to ensure they allow egress traffic from VMs.
Why it's wrong here
Firewall rules are not the cause of routing path selection.
- ✓
Check the route priority (preference) of the default route learned via BGP compared to the default internet gateway route.
Why this is correct
The route with the lowest priority (highest preference) is chosen.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Verify that the Cloud Router is configured to advertise the default route to the VPC.
Why this is correct
Cloud Router must be configured to import routes and the VPC must accept them.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Ensure that the on-premises router is sending the default route with a higher local preference.
Why it's wrong here
Local preference affects outbound from GCP to on-premises, not inbound route selection.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume firewall rules are the issue when traffic fails to route, but the core problem is route selection and propagation—specifically, the default internet gateway route competing with the BGP-learned route, and the Cloud Router's advertisement settings.
Detailed technical explanation
How to think about this question
Cloud Router uses BGP to exchange routes with on-premises routers, and the learned routes are installed in the VPC's route table with a default priority of 1000. The default internet gateway route (0.0.0.0/0) also has a priority of 1000, so when both exist, the route with the lower priority value wins; if priorities are equal, the system uses a tie-breaker that may favor the internet gateway. To force traffic through the VPN, the BGP-learned route must have a lower priority (e.g., 900) or the Cloud Router must be configured to advertise the default route to the VPC (option D), which is not automatic.
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.
TExam Day Tips
- 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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Implementing hybrid interconnectivity — study guide chapter
Learn the concepts, then practise the questions
- →
Implementing hybrid interconnectivity practice questions
Targeted practice on this topic area only
- →
All PCNE questions
497 questions across all exam domains
- →
Google Professional Cloud Network Engineer study guide
Full concept coverage aligned to exam objectives
- →
PCNE practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related PCNE practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Designing, planning, and prototyping a GCP network practice questions
Practise PCNE questions linked to Designing, planning, and prototyping a GCP network.
Implementing hybrid interconnectivity practice questions
Practise PCNE questions linked to Implementing hybrid interconnectivity.
Configuring network services practice questions
Practise PCNE questions linked to Configuring network services.
Implementing network security practice questions
Practise PCNE questions linked to Implementing network security.
Implementing a Virtual Private Cloud practice questions
Practise PCNE questions linked to Implementing a Virtual Private Cloud.
PCNE fundamentals practice questions
Practise PCNE questions linked to PCNE fundamentals.
PCNE scenario practice questions
Practise PCNE questions linked to PCNE scenario.
PCNE troubleshooting practice questions
Practise PCNE questions linked to PCNE troubleshooting.
Practice this exam
Start a free PCNE practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
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: Verify that the VPC's dynamic routing mode is set to 'global' if using regional routing. — Option A is correct because the VPC's dynamic routing mode determines the scope of route propagation. If the VPC uses regional dynamic routing, Cloud Router only propagates routes within the region where the VPN tunnel is attached. A global dynamic routing mode is required for the BGP-learned default route to be available across all regions, ensuring VMs in any region can use the VPN for internet egress.
What should I do if I get this PCNE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Keep practising
More PCNE practice questions
- An organization is migrating to Google Cloud and requires connectivity between their on-premises network and VPC. They p…
- A company is migrating on-premises DNS to Google Cloud. They have a hybrid network using Cloud VPN and want to resolve o…
- A network engineer is configuring a Cloud Router for BGP peering with an on-premises router over a VPN tunnel. The on-pr…
- A company uses Cloud NAT to allow private instances to reach the internet. They notice that egress traffic from Compute…
- Match each VPC networking concept to its definition.
- Drag and drop the steps to troubleshoot a VPN tunnel that is not passing traffic into the correct order.
Last reviewed: Jun 25, 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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.