The answer is to use Private Google Access for VMs that need to access Google APIs, because this allows instances without public IPs to reach Google services over the internal VPC network, eliminating exposure to the public internet. This directly supports the goal of securing a VPC for public web applications by reducing the attack surface—private VMs can still fetch updates or send logs without being directly reachable from the internet. On the Google Professional Cloud Network Engineer exam, this concept tests your understanding of how to combine Private Google Access with Cloud NAT, which provides outbound internet for private VMs while blocking unsolicited inbound traffic. A common trap is confusing Private Google Access with a VPN or direct peering; remember that Private Google Access only works for Google APIs and services, not general internet destinations. Memory tip: “Private Access for Google, Cloud NAT for the rest.”
PCNE Configuring network services Practice Question
This PCNE practice question tests your understanding of configuring network services. 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.
Which THREE actions should you take to secure a VPC that hosts public-facing web applications?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Cloud NAT to allow outbound internet access without public IPs
Cloud NAT enables outbound internet access for private VMs without assigning them public IP addresses, which reduces the attack surface. This is a secure alternative to direct internet access because it allows outbound connections initiated by the VMs while blocking unsolicited inbound traffic from the internet. It works by translating private IP addresses to a set of ephemeral public IPs managed by Google Cloud.
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.
✗
Assign public IP addresses to all VMs for direct internet access
Why it's wrong here
Increases attack surface.
✓
Use Cloud NAT to allow outbound internet access without public IPs
Why this is correct
Provides outbound connectivity without exposing VMs.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable VPC Flow Logs to block malicious traffic
Why it's wrong here
Flow Logs are for logging, not blocking.
✓
Enable Cloud Armor to protect against DDoS and application attacks
Why this is correct
Cloud Armor provides security policies.
Related concept
Read the scenario before looking for a memorised answer.
✓
Use Private Google Access for VMs that need to access Google APIs
Why this is correct
Keeps traffic within Google network.
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 VPC Flow Logs are a security control that can block traffic, when in reality they are only a logging and monitoring feature, not an enforcement mechanism.
Detailed technical explanation
How to think about this question
Cloud NAT uses source network address translation (SNAT) with port address translation (PAT) to map private VMIPs to a pool of external IPs, and it supports manual or automatic NAT IP allocation. VPC Flow Logs sample traffic at a configurable rate (e.g., every 1 in 10 packets) and export logs to Cloud Logging, but they are purely observational; blocking requires integration with tools like Cloud IDS or firewall rules. Private Google Access allows VMs without external IPs to reach Google APIs via the default internet gateway using RFC 1918 addresses, which is essential for secure, private connectivity.
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.
Configuring network services — This question tests Configuring network services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use Cloud NAT to allow outbound internet access without public IPs — Cloud NAT enables outbound internet access for private VMs without assigning them public IP addresses, which reduces the attack surface. This is a secure alternative to direct internet access because it allows outbound connections initiated by the VMs while blocking unsolicited inbound traffic from the internet. It works by translating private IP addresses to a set of ephemeral public IPs managed by Google Cloud.
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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Question Discussion
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