PCNE Configuring Network Services Practice Question
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.
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.
- ✗
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.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.