- A
Enable Private Google Access on the subnet
Why wrong: Private Google Access is for Google APIs, not general internet.
- B
Delete the default route (0.0.0.0/0) from the VPC
Removing the default route prevents direct internet egress.
- C
Add a firewall rule to allow egress to 0.0.0.0/0
Why wrong: This would allow direct internet access, bypassing NAT.
- D
Add a firewall rule to deny egress to 0.0.0.0/0 (except NAT's IP range)
This blocks all outbound except through NAT.
- E
Create a Cloud NAT gateway and assign it to the subnet
Cloud NAT provides outbound connectivity with a managed IP.
Question 108 of 985
PCSE Configuring Network Security Practice Question
This PCSE practice question tests your understanding of configuring 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.
An organization wants to enforce that all egress traffic from a VPC to the internet must go through a Cloud NAT gateway for logging and IP management. They also need to block all other direct outbound traffic. Which THREE steps should they take? (Choose THREE.)
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
✓
Delete the default route (0.0.0.0/0) from the VPC
To force traffic through Cloud NAT, you need to remove the default route (0.0.0.0/0), create a route that only allows traffic to the NAT gateway's IP range (or use a more specific route), and then add a deny egress rule for all other internet traffic.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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 Private Google Access on the subnet
Why it's wrong here
Private Google Access is for Google APIs, not general internet.
- ✓
Delete the default route (0.0.0.0/0) from the VPC
Why this is correct
Removing the default route prevents direct internet egress.
Related concept
CIDR notation defines the prefix length.
- ✗
Add a firewall rule to allow egress to 0.0.0.0/0
Why it's wrong here
This would allow direct internet access, bypassing NAT.
- ✓
Add a firewall rule to deny egress to 0.0.0.0/0 (except NAT's IP range)
- ✓
Create a Cloud NAT gateway and assign it to the subnet
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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.
Visual reference
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCSE subnetting questions on CIDR, address ranges, and subnet selection.
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Configuring Network Security — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this PCSE question test?
Configuring Network Security — This question tests Configuring Network Security — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Delete the default route (0.0.0.0/0) from the VPC — To force traffic through Cloud NAT, you need to remove the default route (0.0.0.0/0), create a route that only allows traffic to the NAT gateway's IP range (or use a more specific route), and then add a deny egress rule for all other internet traffic.
What should I do if I get this PCSE question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCSE subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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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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