PCNE Configuring Network Services Practice Question
Exhibit
Refer to the exhibit. gcloud compute firewall-rules describe allow-ssh Allowed: IPProtocol: tcp ports: ['22'] Direction: INGRESS Source ranges: ['0.0.0.0/0'] Target tags: ['ssh-allowed'] Priority: 1000 A VM with network tag 'ssh-allowed' cannot be reached via SSH from the internet. Other VMs with the same tag work fine.
Refer to the exhibit. A VM with the 'ssh-allowed' tag is unreachable via SSH from the internet, while other VMs with the same tag work. What is the most likely cause?
⚠ Common exam trap
Google Cloud often tests the misconception that a higher priority number means higher priority, when in fact a lower priority number (e.g., 500) takes precedence over a higher one (e.g., 1000), causing candidates to overlook the effect of a deny rule with a lower priority number.
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
✓
A firewall rule with priority 500 denies ingress traffic to the VM's tag or IP range.
The most likely cause is that a firewall rule with priority 500 explicitly denies ingress traffic to the specific VM's tag or IP range, overriding the allow-ssh rule (which has a lower priority, i.e., a higher numerical value). In Google Cloud Platform (GCP), firewall rules are evaluated from lowest to highest priority number, and a deny rule with a lower priority number (e.g., 500) takes precedence over an allow rule with a higher priority number (e.g., 1000). This explains why other VMs with the same 'ssh-allowed' tag remain reachable, as they are not affected by the specific deny rule.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A firewall rule with priority 500 denies ingress traffic to the VM's tag or IP range.
Why this is correct
A higher priority deny rule can override the allow rule.
- ✗
The rule source range is set to 0.0.0.0/0, which includes all internet IPs, so it should allow SSH.
Why it's wrong here
That doesn't explain why only one VM fails.
- ✗
The VM is in a different VPC that does not have the allow-ssh rule.
Why it's wrong here
If the VM is in the same VPC, the rule applies.
- ✗
The firewall rule 'allow-ssh' has a higher priority (1000) than the implicit deny (65535), so it should work.
Why it's wrong here
That is correct, but doesn't explain the issue.
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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.