The answer is to define a Kubernetes NetworkPolicy that allows ingress to backend pods from frontend pods on port 8080. This is the most secure approach because NetworkPolicy enforces native micro-segmentation at the pod level, using label selectors to precisely control pod-to-pod traffic within the cluster, rather than relying on broader node or VPC-level firewall rules. On the Google Professional Cloud Network Engineer exam, this question tests your understanding that Kubernetes-native policies are the recommended method for securing multi-tier applications in GKE, as they integrate directly with the cluster’s network policy engine (Calico or Cilium). A common trap is to suggest using VPC firewall rules or GKE Network Policies based on node tags, but those lack the granularity of pod-level selectors and can introduce unnecessary complexity. Remember the memory tip: “Label your pods, then lock the doors with NetworkPolicy—ingress rules are the key to micro-segmentation.”
PCNE Practice Question: Designing, planning, and prototyping a GCP network
This PCNE practice question tests your understanding of designing, planning, and prototyping a gcp network. 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.
Your company is deploying a multi-tier web application on Google Kubernetes Engine (GKE) with a regional cluster. You need to design network policies to allow traffic only from the frontend pods to the backend pods on port 8080. Which of the following is the most secure and recommended approach?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Define a Kubernetes NetworkPolicy that allows ingress to backend pods from frontend pods on port 8080.
A Kubernetes NetworkPolicy is the native and most secure way to control pod-to-pod traffic within a GKE cluster. By defining an ingress rule that allows traffic only from frontend pods (selected via pod labels) to backend pods on TCP port 8080, you enforce micro-segmentation at the pod level, which is the recommended practice for multi-tier applications. This approach works regardless of the underlying node or VPC configuration and is fully integrated with GKE's network policies engine (Calico or Cilium).
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.
✓
Define a Kubernetes NetworkPolicy that allows ingress to backend pods from frontend pods on port 8080.
Why this is correct
NetworkPolicy is the native Kubernetes mechanism for pod-level traffic control.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure Private Service Connect to restrict access to backend pods.
Why it's wrong here
Private Service Connect is for private access to managed services, not pod isolation.
✗
Create VPC firewall rules to allow ingress from frontend pods to backend pods on port 8080.
Why it's wrong here
VPC firewall rules apply to VM instances, not Kubernetes pods.
✗
Use Cloud Armor security policies to restrict traffic to backend pods.
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse VPC firewall rules (which control traffic at the node level) with Kubernetes NetworkPolicy (which controls traffic at the pod level), leading them to choose option C, even though pod IPs are ephemeral and not directly manageable via VPC firewall rules.
Detailed technical explanation
How to think about this question
Kubernetes NetworkPolicy uses iptables or eBPF rules (depending on the CNI plugin) to filter traffic at the pod network interface. In GKE, the network policy enforcement is handled by the Dataplane V2 (based on Cilium/eBPF) or by Calico, which allows for high-performance, scalable policy enforcement without modifying the VPC. A common subtlety is that NetworkPolicy is namespace-scoped and requires proper pod selector labels; if no policy is applied, all traffic is allowed by default.
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
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
Designing, planning, and prototyping a GCP network — This question tests Designing, planning, and prototyping a GCP network — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Define a Kubernetes NetworkPolicy that allows ingress to backend pods from frontend pods on port 8080. — A Kubernetes NetworkPolicy is the native and most secure way to control pod-to-pod traffic within a GKE cluster. By defining an ingress rule that allows traffic only from frontend pods (selected via pod labels) to backend pods on TCP port 8080, you enforce micro-segmentation at the pod level, which is the recommended practice for multi-tier applications. This approach works regardless of the underlying node or VPC configuration and is fully integrated with GKE's network policies engine (Calico or Cilium).
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 →
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.
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.