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Designing, Planning, and Prototyping a GCP Network →easyMultiple ChoiceObjective-mapped

PCNE Practice Question: Designing, Planning, and Prototyping a GCP Network

Network Topology
gcloud compute firewall-rules listfilter="network=my-vpc"format=jsonRefer to the exhibit.Output:"name": "allow-ssh","network": "my-vpc","sourceRanges": ["0.0.0.0/0"],"allowed": [{"IPProtocol": "tcp", "ports": ["22"]}],"direction": "INGRESS","priority": 1000},"name": "allow-rdp","sourceRanges": ["10.0.0.0/8"],"allowed": [{"IPProtocol": "tcp", "ports": ["3389"]}],

Refer to the exhibit. A network engineer reviews the firewall rules in a VPC. What is the most significant security concern?

⚠ Common exam trap

Google Cloud often tests the misconception that a missing explicit deny rule is a security risk, but in GCP VPC, the implicit deny at the end of the rule evaluation makes an explicit deny unnecessary unless you need to override a higher-priority allow rule.

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

✓

SSH is allowed from any source.

Allowing SSH (TCP/22) from any source (0.0.0.0/0) exposes the VPC instances to brute-force attacks, unauthorized access, and potential compromise. This violates the principle of least privilege and is a critical security misconfiguration in a VPC firewall 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.

  • ✗

    There is no deny rule.

    Why it's wrong here

    Default deny is implicit; having no explicit deny is normal.

  • ✗

    RDP is allowed from 10.0.0.0/8.

    Why it's wrong here

    This is a private range and acceptable for internal access.

  • ✓

    SSH is allowed from any source.

    Why this is correct

    0.0.0.0/0 includes all public IPs, which is insecure.

  • ✗

    Firewall rules are not in order.

    Why it's wrong here

    No conflicting rules; order is not a concern here.

About these practice questions

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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.