- A
Firewall rules are blocking traffic from health check ranges
Correct. Health check ranges must be allowed by firewall.
- B
The backend service is not using an instance group
Why wrong: Backend services can use instance groups or NEGs.
- C
The health check protocol should be HTTPS
Why wrong: If the server responds on HTTP, HTTP is fine.
- D
The health check interval is too long
Why wrong: Interval affects timing, not success/failure.
Question 657 of 982
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.
While configuring a health check for a backend service, an engineer notices that the health check is failing even though the instances are healthy. The health check is HTTP on port 80 with a request path of /health. The instances respond to curl http://localhost:80/health with 200 OK. What is a likely cause?
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
✓
Firewall rules are blocking traffic from health check ranges
Health checks originate from Google's health check systems, which use source IP ranges. A firewall rule must allow traffic from those ranges. Other options are not as likely.
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.
- ✓
Firewall rules are blocking traffic from health check ranges
Why this is correct
Correct. Health check ranges must be allowed by firewall.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The backend service is not using an instance group
Why it's wrong here
Backend services can use instance groups or NEGs.
- ✗
The health check protocol should be HTTPS
Why it's wrong here
If the server responds on HTTP, HTTP is fine.
- ✗
The health check interval is too long
Why it's wrong here
Interval affects timing, not success/failure.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Identify which PCNE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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Configuring Network Services — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
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: Firewall rules are blocking traffic from health check ranges — Health checks originate from Google's health check systems, which use source IP ranges. A firewall rule must allow traffic from those ranges. Other options are not as likely.
What should I do if I get this PCNE question wrong?
Identify which PCNE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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: Jul 4, 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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