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Troubleshooting practice questions

Practise Google Professional Cloud Network Engineer Troubleshooting practice questions — original exam-style scenarios with answer choices, explanations, and analysis of common mistakes.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Reviewed byJohnson Ajibi· MSc IT Security
20 questionsDomain: Troubleshooting
Practice 10 questionsBrowse domain →

What the exam tests

What to know about Troubleshooting

Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.

How the topic appears in realistic exam-style scenarios.

Which detail in the question changes the correct answer.

How to eliminate plausible but wrong options.

How to connect the question back to the wider exam objective.

Watch out for

Common Troubleshooting exam traps

  • ▸Answering from memory before reading the full scenario.
  • ▸Missing a constraint such as cost, availability, security, scope or command context.
  • ▸Choosing a broad answer when the question asks for the most specific fix.
  • ▸Ignoring why the wrong options are tempting.

Practice set

Troubleshooting questions

20 questions · select your answer, then reveal the explanation

Question 1hardmultiple choice
Review the full subnetting walkthrough →

A network engineer is troubleshooting connectivity issues between two Compute Engine instances in the same VPC but different subnets (us-east1 and europe-west1). The engineer suspects an MTU issue. What is the default MTU for traffic within Google Cloud, and what MTU should the engineer expect when packets traverse the internet?

Question 2hardmultiple choice
Review the full subnetting walkthrough →

An engineer is troubleshooting a VPC Network Peering connection between two VPCs. The peering is established, but traffic from VPC A to VPC B is not reaching a specific subnet. Both VPCs have custom routes. What is the most likely cause?

Question 3hardmulti select
Open the full BGP breakdown →

A network engineer is troubleshooting a BGP session between an on-premises router and a Cloud Router. The BGP session state is 'CONNECT' and never transitions to 'ESTABLISHED'. The engineer has verified that the Cloud Router and on-premises router have the same BGP ASN, and that the peer IP addresses are correctly configured. Which two additional steps should the engineer take to resolve this issue? (Choose TWO.)

Question 4hardmulti select
Open the full BGP breakdown →

An engineer is troubleshooting a High Availability VPN setup. The VPN tunnels are established, but the BGP sessions are flapping. Which THREE factors could cause this? (Choose THREE.)

Question 5hardmulti select
Read the full Troubleshooting explanation →

A network engineer is troubleshooting a global HTTPS load balancer that is not serving traffic to some users. The load balancer has a backend service with a zonal NEG in us-central1-a. Users report intermittent 502 errors. Which two checks should the engineer perform? (Choose two.)

Question 6mediummultiple choice
Read the full NAT/PAT explanation →

An engineer is troubleshooting outbound connectivity from a Compute Engine instance that has no external IP. The instance needs to reach an external service on the internet. Cloud NAT is configured on the VPC network. However, the instance cannot connect. What is the most likely cause?

Question 7hardmultiple choice
Open the full BGP breakdown →

A network engineer is troubleshooting BGP session flaps between a Cloud Router and an on-premises router. The Cloud Router logs show that the session goes down and up repeatedly every few minutes. What is the most common cause of such flapping?

Question 8hardmultiple choice
Review the full routing breakdown →

An engineer is troubleshooting asymmetric routing between two VPCs connected via VPC peering. They notice that return traffic takes a different path. What is a common cause of asymmetric routing in this scenario?

Question 9easymultiple choice
Open the full BGP breakdown →

You are troubleshooting an HA VPN connection between Google Cloud and on-premises. The tunnels appear as 'UP' but no routes are exchanged. The Cloud Router logs show 'BGP session state: IDLE'. What is the most likely cause?

Question 10hardmultiple choice
Read the full VPN explanation →

A network engineer is troubleshooting a failing HA VPN tunnel. They need to view VPN gateway logs to identify the issue. Which Google Cloud service should they use to access the logs?

Question 11mediummultiple choice
Read the full Troubleshooting explanation →

An engineer is troubleshooting high latency between a Compute Engine instance in us-central1 and an instance in europe-west1. Which tool can show per-region latency and packet loss?

Question 12easymulti select
Read the full Troubleshooting explanation →

A network engineer is troubleshooting high latency between two VM instances in different GCP regions. Which TWO tools can help identify packet loss and latency issues? (Choose TWO.)

Question 13easymultiple choice
Read the full VPN explanation →

A network engineer is troubleshooting connectivity from an on-premises network to a GCE VM through a VPN tunnel. The tunnel is established, but traffic is not reaching the VM. What should the engineer check first?

Question 14mediummatching
Read the full Troubleshooting explanation →

Match each network troubleshooting command/tool to its function.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Tests basic connectivity to an IP address

Traces the path packets take to a destination

Displays network connections and listening ports

Queries DNS to resolve a hostname

Captures and analyzes network packets

Question 15hardmultiple choice
Open the full BGP breakdown →

A network engineer is troubleshooting an HA VPN setup between Google Cloud and an on-premises data center. The two tunnels are established, and BGP sessions are up on both tunnels. However, traffic from Google Cloud to the on-premises network is only using one tunnel, even though both BGP sessions are advertising the same routes. What is the most likely cause?

Question 16easymulti select
Open the full VLAN trunking answer →

A company is troubleshooting connectivity issues between their on-premises network and Google Cloud over a Dedicated Interconnect. They can ping the VLAN attachment IP but cannot reach Compute Engine instances. Which TWO checks should they perform?

Question 17hardmultiple choice
Open the full BGP breakdown →

A network engineer is troubleshooting connectivity between an on-premises network and Google Cloud. The on-premises router has two BGP sessions configured for redundancy with a Cloud Router. The engineer runs the command above. Which issue does the output indicate?

Exhibit

Refer to the exhibit.

```
$ gcloud compute routers get-status my-router --region=us-central1
kind: compute#routerStatusResponse
result:
  router: my-router
  bgpPeerStatus:
  - name: peer-a
    ipAddress: 169.254.1.1
    peerIpAddress: 169.254.1.2
    status: UP
    numUp: 1
    numLearned: 0
    advertisedRoutes:
    - 10.0.0.0/8
    learnedRoutes: []
  - name: peer-b
    ipAddress: 169.254.2.1
    peerIpAddress: 169.254.2.2
    status: DOWN
    numUp: 0
    numLearned: 0
    advertisedRoutes: []
    learnedRoutes: []
```
Question 18mediummulti select
Read the full Troubleshooting explanation →

Which THREE of the following are benefits of using VPC Flow Logs?

Question 19hardmulti select
Read the full VPN explanation →

You are troubleshooting a failing HA VPN tunnel between GCP and on-premises. The tunnel status shows 'Tunnel is down' in Cloud Console. Which TWO steps should you take to diagnose the issue? (Choose two.)

Question 20mediummulti select
Read the full NAT/PAT explanation →

An engineer needs to monitor Cloud NAT gateway usage for cost allocation and troubleshooting. Which TWO types of logs should they enable? (Choose TWO.)

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Focused Troubleshooting sessions

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Every question in these sessions is drawn from the Troubleshooting domain — nothing else.

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Frequently asked questions

What does the PCNE exam test about Troubleshooting?
Troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.
How should I use these practice questions?
Select your answer before revealing the explanation. Then read why each option is right or wrong — this active recall approach builds retention far faster than re-reading notes.
Can I practise just Troubleshooting questions in a focused session?
Yes — the session launcher on this page draws every question from the Troubleshooting domain. Use a 10-question session first to gauge your baseline, then move to 20 or 30 once the weak spots are clear.
Where can I practise other PCNE topics?
Use the topic links above to move to related areas, or go back to the PCNE question bank to see all topics.
Are these real exam questions or dumps?
These are original practice questions written to test the same concepts the PCNE exam covers. They are not copied from any real exam or dump site.