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Cloud Digital Leader Practice Question: A company's IT team is planning its network…
A company's IT team is planning its network architecture for a Google Cloud deployment. They want to ensure that their development, staging, and production environments are completely isolated from each other at the network level. What is the most effective way to achieve this isolation in Google Cloud?
⚠ Common exam trap
Many exam-takers assume firewall rules or IAM can achieve the same level of isolation as separate VPCs, but network-level isolation requires separate routing domains, not just access controls or IP address segmentation.
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
✓
Deploying each environment (dev, staging, prod) in separate VPC networks — optionally in separate Google Cloud projects — to achieve complete network isolation with no default connectivity between environments
Deploying each environment in separate VPC networks (optionally in separate projects) provides complete network isolation by default. In Google Cloud, VPC networks are isolated entities with no inherent peering or connectivity; traffic between them requires explicit VPC peering or VPN configurations. This ensures that development, staging, and production environments cannot communicate at the network layer unless intentionally connected, meeting the requirement for complete isolation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Using separate subnets within the same VPC for each environment, with firewall rules blocking cross-subnet traffic
Why it's wrong here
Subnets in the same VPC share the VPC's IP address space and routing table. Firewall rules can restrict traffic but do not provide the same level of isolation as separate VPCs. VMs in the same VPC can reach each other via internal routes even with firewall rules.
- ✓
Deploying each environment (dev, staging, prod) in separate VPC networks — optionally in separate Google Cloud projects — to achieve complete network isolation with no default connectivity between environments
Why this is correct
Separate VPCs provide true network isolation. By default, separate VPCs have no connectivity. Traffic between them requires explicit peering, VPN, or Shared VPC configuration. Using separate projects adds IAM-level access control on top of network isolation.
- ✗
Using different IP address ranges for each environment within the same network
Why it's wrong here
Different IP address ranges within the same VPC correspond to subnets, but subnets are not isolated by default: every subnet in a VPC is connected via the VPC’s internal routing table. A VM in 10.0.1.0/24 can reach a VM in 10.0.2.0/24 using its internal IP because system-generated routes cover all subnets in the VPC. Therefore, varying IP ranges merely partitions the address space for addressing or firewall rule naming, not for isolation. To truly isolate dev, staging, and prod, you must use separate VPC networks (or projects), where no default routes exist between environments.
- ✗
Using Cloud IAM to restrict developers from accessing production resources, which achieves the same isolation as network separation
Why it's wrong here
IAM controls who can access resources through the GCP management plane (console, API). Network isolation controls data plane traffic between resources. Both are needed; IAM alone does not prevent network-level communication between resources that don't have IAM restrictions.
Go deeper
Related to this question
Learn chapter
Google Cloud Regions, Zones, and Network PoPs
Key term
VPC
A Virtual Private Cloud (VPC) is a logically isolated section of a cloud provider's network where you can launch and manage resources like servers and databases with complete control over IP addressing, subnets, route tables, and security.
Key term
VPC peering
VPC peering is a direct network connection between two virtual private clouds that allows them to communicate using private IP addresses as if they were part of the same network.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This GCDL 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 GCDL exam.