PCNE Configuring network services Practice Question
This PCNE practice question tests your understanding of configuring network services. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 to allow private instances to access the internet. They notice that some instances are not able to reach certain external services. Which THREE steps should they take to troubleshoot?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check if the external service is blocking the Cloud NAT IP addresses.
Option A is correct because Cloud NAT uses a set of public IP addresses for outbound traffic. If the external service has firewall rules or access control lists that block these specific IP addresses, the instances will be unable to reach it. Checking for IP-based blocking is a standard first step in troubleshooting connectivity issues through a NAT gateway.
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.
✓
Check if the external service is blocking the Cloud NAT IP addresses.
Why this is correct
Some external services may block specific IP ranges, including NATIPs.
Related concept
Read the scenario before looking for a memorised answer.
✓
Verify that the VPC firewall rules allow egress traffic from the instances.
Why this is correct
Cloud NAT requires firewall rules to allow outbound traffic.
Related concept
Read the scenario before looking for a memorised answer.
✗
Ensure that the VPC has a default route to the internet gateway.
Why it's wrong here
Cloud NAT automatically uses the default route; no explicit route to internet gateway needed.
✓
Verify that the Cloud Router associated with Cloud NAT is healthy and has established BGP sessions.
Why this is correct
Cloud NAT uses routes from Cloud Router; if BGP is down, NAT may not work properly.
Related concept
Read the scenario before looking for a memorised answer.
✗
Check the DNS resolution for the external service.
Why it's wrong here
DNS resolution is not related to Cloud NAT functionality.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that DNS resolution is the primary cause of connectivity failures to external services, when in fact the issue is often at the network layer (e.g., IP blocking or firewall rules) rather than the application layer.
Detailed technical explanation
How to think about this question
Cloud NAT uses Source Network Address Translation (SNAT) to map private instance IPs to a pool of public IPs. When an external service blocks these public IPs, TCP resets or ICMP unreachable messages may be returned, but often the connection simply times out. Checking Cloud NAT logs in Cloud Logging can reveal the source IPs used and any dropped packets, helping to correlate with the external service's blocklist.
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: Check if the external service is blocking the Cloud NAT IP addresses. — Option A is correct because Cloud NAT uses a set of public IP addresses for outbound traffic. If the external service has firewall rules or access control lists that block these specific IP addresses, the instances will be unable to reach it. Checking for IP-based blocking is a standard first step in troubleshooting connectivity issues through a NAT gateway.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.