The answer is that VPC peering can be established between VPCs in different organizations, and it requires non-overlapping IP ranges. This is correct because VPC peering is a direct, private connection that routes traffic using internal IPs, and overlapping CIDR blocks would create routing conflicts, making the peering impossible to establish. On the Google Professional Cloud Network Engineer exam, this concept tests your understanding of cross-project and cross-organization networking, often appearing in scenario-based questions where you must identify valid peering configurations. A common trap is assuming peering is limited to the same organization or that overlapping subnets are acceptable if you use custom routes. Remember the key requirement: peering is transitive only through a hub, not across multiple peers, and the subnets must be unique. For a quick memory tip, think “Peering = Private + No Overlap,” and recall that organizations are just logical containers in Google Cloud, so peering can span them freely as long as the IP spaces do not collide.
PCNE Implementing a Virtual Private Cloud Practice Question
This PCNE practice question tests your understanding of implementing a virtual private cloud. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO statements about VPC peering are correct?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VPC peering requires that all subnet CIDR ranges be unique across both VPCs.
Peering can be across organizations and requires non-overlapping subnets.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
VPC peering allows traffic without firewall rules if both VPCs are in the same project.
Why it's wrong here
Firewall rules are always enforced for peered traffic.
✗
VPC peering automatically exports custom routes.
Why it's wrong here
Custom route export must be explicitly enabled.
✗
VPC peering can only be established for VPCs in the same region.
Why it's wrong here
Peering works across regions.
✓
VPC peering requires that all subnet CIDR ranges be unique across both VPCs.
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCNE subnetting questions on CIDR, address ranges, and subnet selection.
Implementing a Virtual Private Cloud — This question tests Implementing a Virtual Private Cloud — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: VPC peering requires that all subnet CIDR ranges be unique across both VPCs. — Peering can be across organizations and requires non-overlapping subnets.
What should I do if I get this PCNE question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related PCNE subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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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.
Question Discussion
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