- A
External IP addresses on the web servers
External IPs allow inbound internet traffic to web servers.
- B
VPC Network Peering with a partner network
Why wrong: Not needed for internal traffic within the VPC.
- C
Shared VPC
Why wrong: Unnecessary; the application can be in a single VPC.
- D
Cloud NAT for database servers to access the internet
Cloud NAT provides outbound-only internet for private instances.
- E
Firewall rules to restrict traffic between subnets
Firewall rules can allow only web-to-db traffic.
Question 560 of 1,000
PCNE Practice Question: Designing, Planning, and Prototyping a GCP Network
This PCNE practice question tests your understanding of designing, planning, and prototyping a gcp network. 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.
A company is designing a VPC for a multi-tier web application. They need to ensure that the web servers can be reached from the internet, but the database servers should only be accessible from the web servers. Which three components should they use to achieve this? (Choose THREE.)
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
✓
External IP addresses on the web servers
Firewall rules control traffic between tiers; Cloud NAT provides outbound internet for private instances; and external IPs allow inbound internet traffic to web servers.
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.
- ✓
External IP addresses on the web servers
- ✗
VPC Network Peering with a partner network
Why it's wrong here
Not needed for internal traffic within the VPC.
- ✗
Shared VPC
Why it's wrong here
Unnecessary; the application can be in a single VPC.
- ✓
Cloud NAT for database servers to access the internet
- ✓
Firewall rules to restrict traffic between subnets
Common exam traps
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
Visual reference
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.
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Designing, Planning, and Prototyping a GCP Network — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
Designing, Planning, and Prototyping a GCP Network — This question tests Designing, Planning, and Prototyping a GCP Network — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: External IP addresses on the web servers — Firewall rules control traffic between tiers; Cloud NAT provides outbound internet for private instances; and external IPs allow inbound internet traffic to web servers.
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.
About these practice questions
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Last reviewed: Jul 4, 2026
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.
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