- A
Use VPC Service Controls to create a service perimeter that restricts access to Cloud Storage, and configure the VMs to use Private Google Access
Why wrong: VPC Service Controls restrict access from outside to Google APIs, but do not control VM egress traffic to arbitrary IPs. Firewall rules are needed.
- B
Create a deny-all egress firewall rule with priority 65535 and target tags 'storage-only', then create a higher-priority allow rule for traffic to 0.0.0.0/0 with destination tags 'storage-only'
Why wrong: This would allow traffic to any IP, not specifically Cloud Storage.
- C
Create a firewall rule that allows egress to the private IP ranges used by Cloud Storage (e.g., 199.36.153.4/30) and target the VMs using service accounts, then add a lower-priority deny-all egress rule
This correctly allows only Cloud Storage traffic using service account targets for VMs, with a deny-all catch-all.
- D
Create a network firewall policy that allows egress to the Cloud Storage API endpoint (storage.googleapis.com) and attach it to the VPC
Why wrong: Network firewall policies operate at the VPC level, not per VM. Also, destination is an IP, not a domain name.
PCSE Configuring Network Security Practice Question
This PCSE practice question tests your understanding of configuring 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.
Your organization wants to enforce that all VMs in a project can only communicate with a specific Cloud Storage bucket, and no other external IP addresses. You need to configure firewall rules to achieve this. Which approach should you take?
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
Create a firewall rule that allows egress to the private IP ranges used by Cloud Storage (e.g., 199.36.153.4/30) and target the VMs using service accounts, then add a lower-priority deny-all egress rule
To restrict VMs to only communicate with a specific Cloud Storage bucket, you should use a firewall rule with service account targets (for the VMs) and deny all egress traffic except to the private Google Access IP ranges for Cloud Storage. Using service account targets is preferred for security as it follows the principle of least privilege and is independent of VM instance changes.
Key principle: Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use VPC Service Controls to create a service perimeter that restricts access to Cloud Storage, and configure the VMs to use Private Google Access
- ✗
Create a deny-all egress firewall rule with priority 65535 and target tags 'storage-only', then create a higher-priority allow rule for traffic to 0.0.0.0/0 with destination tags 'storage-only'
Why it's wrong here
This would allow traffic to any IP, not specifically Cloud Storage.
- ✓
Create a firewall rule that allows egress to the private IP ranges used by Cloud Storage (e.g., 199.36.153.4/30) and target the VMs using service accounts, then add a lower-priority deny-all egress rule
Why this is correct
This correctly allows only Cloud Storage traffic using service account targets for VMs, with a deny-all catch-all.
Related concept
Authentication checks who the user is.
- ✗
Create a network firewall policy that allows egress to the Cloud Storage API endpoint (storage.googleapis.com) and attach it to the VPC
Common exam traps
Common exam trap: authentication is not authorization
Logging in proves the user can authenticate. It does not automatically mean the user is allowed to enter privileged or configuration mode. Watch for AAA authorization, privilege level and command authorization details.
Detailed technical explanation
How to think about this question
This kind of question is testing the difference between identity and permission. A user may successfully log in to a router because authentication is working, but still fail to enter configuration mode because authorization is missing, misconfigured or mapped to a lower privilege level.
KKey Concepts to Remember
- Authentication checks who the user is.
- Authorization controls what the user is allowed to do after login.
- Privilege levels affect access to EXEC and configuration commands.
- AAA, TACACS+ and RADIUS can separate login success from command access.
TExam Day Tips
- Do not assume successful login means full administrative access.
- Look for words such as cannot enter configuration mode, privilege level, authorization or command access.
- Separate login problems from permission problems before choosing the answer.
Key takeaway
Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
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.
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related PCSE questions on access control and AAA configuration.
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Configuring Network Security — study guide chapter
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FAQ
Questions learners often ask
What does this PCSE question test?
Configuring Network Security — This question tests Configuring Network Security — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: Create a firewall rule that allows egress to the private IP ranges used by Cloud Storage (e.g., 199.36.153.4/30) and target the VMs using service accounts, then add a lower-priority deny-all egress rule — To restrict VMs to only communicate with a specific Cloud Storage bucket, you should use a firewall rule with service account targets (for the VMs) and deny all egress traffic except to the private Google Access IP ranges for Cloud Storage. Using service account targets is preferred for security as it follows the principle of least privilege and is independent of VM instance changes.
What should I do if I get this PCSE question wrong?
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related PCSE questions on access control and AAA configuration.
What is the key concept behind this question?
Authentication checks who the user is.
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Last reviewed: Jul 4, 2026
This PCSE 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 PCSE exam.
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