- A
Ensure the VMs have a default route (0.0.0.0/0) with next hop set to the Cloud NAT gateway's subnet
The default route sends traffic to Cloud NAT.
- B
Configure IAM conditions on the Cloud NAT resource to restrict which VMs can use it
Why wrong: Cloud NAT does not support IAM conditions for traffic selection.
- C
Enable VPC Flow Logs on the subnet to monitor which NAT IPs are used
Why wrong: Flow logs monitor traffic but do not affect which NAT IPs are used.
- D
Create a separate Cloud NAT gateway with the desired IPs and associate it with the VMs via a subnet or tags
Multiple Cloud NAT gateways can be created per region, each with its own IPs.
- E
Configure VPC firewall rules to allow egress from the VMs to the internet
Firewall rules must allow outbound traffic.
PCNE Implementing network security Practice Question
This PCNE practice question tests your understanding of implementing network security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 company is using Cloud NAT for outbound internet access. They want to ensure that traffic from certain VMs always uses a specific set of NAT IPs for auditing purposes. Which three steps are necessary to achieve this? (Choose THREE.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"always"Why it matters: Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
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
Ensure the VMs have a default route (0.0.0.0/0) with next hop set to the Cloud NAT gateway's subnet
Option A is correct because for Cloud NAT to function, the VM must have a default route (0.0.0.0/0) that points to the Cloud NAT gateway's subnet as the next hop. Without this route, the VM's outbound traffic will not be directed to the NAT gateway, and the NAT IPs will not be used. This ensures that traffic from the VM is routed through the NAT gateway, allowing the specific set of NAT IPs to be applied for auditing.
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.
- ✓
Ensure the VMs have a default route (0.0.0.0/0) with next hop set to the Cloud NAT gateway's subnet
Why this is correct
The default route sends traffic to Cloud NAT.
Clue confirmation
The clue word "always" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Configure IAM conditions on the Cloud NAT resource to restrict which VMs can use it
Why it's wrong here
Cloud NAT does not support IAM conditions for traffic selection.
- ✗
Enable VPC Flow Logs on the subnet to monitor which NAT IPs are used
- ✓
Create a separate Cloud NAT gateway with the desired IPs and associate it with the VMs via a subnet or tags
- ✓
Configure VPC firewall rules to allow egress from the VMs to the internet
Why this is correct
Firewall rules must allow outbound traffic.
Clue confirmation
The clue word "always" in the question point toward this answer.
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 IAM conditions can control Cloud NAT usage per VM, but in reality, Cloud NAT uses subnet or tag-based association, not IAM, and VPC Flow Logs are for monitoring, not configuration.
Detailed technical explanation
How to think about this question
Cloud NAT uses a NAT gateway resource that is associated with a Cloud Router and a specific region. When you create a separate Cloud NAT gateway with desired IPs and associate it with VMs via subnet or tags (Option D), the VMs' outbound traffic is source NATed to those IPs. The default route (Option A) must point to the Cloud NAT gateway's subnet (typically the VPC's default internet gateway route, but for NAT, it's the gateway's subnet) to ensure traffic is intercepted. Firewall rules (Option E) must allow egress traffic to the internet; otherwise, the NAT gateway will drop the packets even if routing is correct.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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.
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Implementing network security — study guide chapter
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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: Ensure the VMs have a default route (0.0.0.0/0) with next hop set to the Cloud NAT gateway's subnet — Option A is correct because for Cloud NAT to function, the VM must have a default route (0.0.0.0/0) that points to the Cloud NAT gateway's subnet as the next hop. Without this route, the VM's outbound traffic will not be directed to the NAT gateway, and the NAT IPs will not be used. This ensures that traffic from the VM is routed through the NAT gateway, allowing the specific set of NAT IPs to be applied for auditing.
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.
Are there clue words in this question I should notice?
Yes — watch for: "always". Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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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