- A
Enable Cloud NAT and configure a firewall rule to allow egress to 0.0.0.0/0
Why wrong: Cloud NAT provides internet access, but for Google APIs Private Google Access is sufficient and more secure.
- B
Configure a Service Directory endpoint and attach an IAM policy to the bucket allowing access only from that endpoint
Why wrong: Service Directory is not used for network access control to Cloud Storage.
- C
Create a firewall rule allowing egress to the storage.googleapis.com service IP range and enable VPC flow logs
Why wrong: Firewall rule alone does not restrict access to a specific VPC; VPC Service Controls is needed.
- D
Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project
Private Google Access enables internal IP access to Google APIs, and VPC Service Controls restricts access to the perimeter.
Quick Answer
The correct configuration requires enabling Private Google Access on the subnet and creating a VPC Service Controls perimeter that includes the bucket project. Private Google Access allows VM instances with only internal IP addresses to reach Google APIs like storage.googleapis.com over the Google Cloud backbone, bypassing the public internet entirely. VPC Service Controls then enforce a security perimeter around the project containing the bucket, preventing data exfiltration even if the bucket is accidentally made public, and restricting access to only authorized VPC networks. On the Google Professional Cloud Network Engineer exam, this pairing tests your understanding of how to combine network-level private connectivity with policy-level data boundaries. A common trap is thinking that enabling Private Google Access alone is sufficient—it provides the path, but without the perimeter, any VM on the internet could still reach the bucket. Memory tip: think of Private Google Access as the “private road” and VPC Service Controls as the “gated community” around the bucket’s project.
PCNE Implementing network security Practice Question
This PCNE practice question tests your understanding of implementing network security. 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.
An organization wants to restrict access to a Cloud Storage bucket so that only VMs within a specific VPC network can download objects. They are using VPC Service Controls and Private Google Access. Which configuration is required?
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
Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project
D is correct because VPC Service Controls create a security perimeter around the Cloud Storage bucket's project, preventing data exfiltration even if the bucket is publicly accessible. Private Google Access on the subnet allows VMs to reach Google APIs (including storage.googleapis.com) via internal IPs, avoiding the public internet. Together, they ensure only VMs within the specified VPC network can download objects, as the perimeter restricts access to authorized networks and Private Google Access provides the private connectivity path.
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.
- ✗
Enable Cloud NAT and configure a firewall rule to allow egress to 0.0.0.0/0
Why it's wrong here
Cloud NAT provides internet access, but for Google APIs Private Google Access is sufficient and more secure.
- ✗
Configure a Service Directory endpoint and attach an IAM policy to the bucket allowing access only from that endpoint
Why it's wrong here
Service Directory is not used for network access control to Cloud Storage.
- ✗
Create a firewall rule allowing egress to the storage.googleapis.com service IP range and enable VPC flow logs
Why it's wrong here
Firewall rule alone does not restrict access to a specific VPC; VPC Service Controls is needed.
- ✓
Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project
Why this is correct
Private Google Access enables internal IP access to Google APIs, and VPC Service Controls restricts access to the perimeter.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that firewall rules alone (Option C) or NAT (Option A) are sufficient for restricting access, when in fact VPC Service Controls are required to enforce network-level boundaries beyond IAM and connectivity.
Detailed technical explanation
How to think about this question
VPC Service Controls work by creating a perimeter that defines allowed projects and networks; when a bucket is inside the perimeter, access is denied from outside the perimeter even if IAM permissions allow it. Private Google Access uses the subnet's internal IP to route traffic to Google APIs via the Google Cloud private backbone, which is required for VMs without external IPs to reach storage.googleapis.com. A common real-world scenario is a data lake bucket that must be accessed only by analytics VMs in a private subnet, preventing data leakage to the internet or other networks.
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.
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FAQ
Questions learners often ask
What does this PCNE question test?
Implementing network security — This question tests Implementing network security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project — D is correct because VPC Service Controls create a security perimeter around the Cloud Storage bucket's project, preventing data exfiltration even if the bucket is publicly accessible. Private Google Access on the subnet allows VMs to reach Google APIs (including storage.googleapis.com) via internal IPs, avoiding the public internet. Together, they ensure only VMs within the specified VPC network can download objects, as the perimeter restricts access to authorized networks and Private Google Access provides the private connectivity path.
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.
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Last reviewed: Jun 30, 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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