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Implementing network securityhardMultiple ChoiceObjective-mapped

PCNE Implementing network security Practice Question

An organization wants to restrict access to a Cloud Storage bucket so that only VMs within a specific VPC network can download objects. They are using VPC Service Controls and Private Google Access. Which configuration is required?

⚠ Common exam trap

Google Cloud often tests the misconception that firewall rules alone (Option C) or NAT (Option A) are sufficient for restricting access, when in fact VPC Service Controls are required to enforce network-level boundaries beyond IAM and connectivity.

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

Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project

D is correct because VPC Service Controls create a security perimeter around the Cloud Storage bucket's project, preventing data exfiltration even if the bucket is publicly accessible. Private Google Access on the subnet allows VMs to reach Google APIs (including storage.googleapis.com) via internal IPs, avoiding the public internet. Together, they ensure only VMs within the specified VPC network can download objects, as the perimeter restricts access to authorized networks and Private Google Access provides the private connectivity path.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Enable Cloud NAT and configure a firewall rule to allow egress to 0.0.0.0/0

    Why it's wrong here

    Cloud NAT provides internet access, but for Google APIs Private Google Access is sufficient and more secure.

  • Configure a Service Directory endpoint and attach an IAM policy to the bucket allowing access only from that endpoint

    Why it's wrong here

    Service Directory is not used for network access control to Cloud Storage.

  • Create a firewall rule allowing egress to the storage.googleapis.com service IP range and enable VPC flow logs

    Why it's wrong here

    Firewall rule alone does not restrict access to a specific VPC; VPC Service Controls is needed.

  • Enable Private Google Access on the subnet and create a VPC Service Controls perimeter that includes the bucket project

    Why this is correct

    Private Google Access enables internal IP access to Google APIs, and VPC Service Controls restricts access to the perimeter.

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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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.