Question 982 of 1,000
Implementing VPC InstancesmediumMultiple ChoiceObjective-mapped

PCNE Implementing VPC Instances Practice Question

This PCNE practice question tests your understanding of implementing vpc instances. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 has Compute Engine instances without external IPs in a VPC. They need to reach Google APIs such as Cloud Storage and BigQuery. Which configuration will meet this requirement with minimal cost and operational overhead?

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

Configure the subnet to have Private Google Access enabled. Ensure the instances have the appropriate DNS resolution for private.googleapis.com.

Private Google Access enables instances without external IPs to reach Google APIs using internal IPs via the default internet gateway or VPC peering. Configuring a Private Google Access enabled subnet is the simplest and cheapest option, as it does not require NAT or additional instances.

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.

  • Configure the subnet to have Private Google Access enabled. Ensure the instances have the appropriate DNS resolution for private.googleapis.com.

    Why this is correct

    This enables instances to reach Google APIs via internal IPs without needing external IPs or NAT.

    Related concept

    CIDR notation defines the prefix length.

  • Set up a Squid proxy on a bastion host with an external IP and route all API traffic through it.

    Why it's wrong here

    This is complex and unnecessary; Private Google Access is designed for this scenario.

  • Create a Cloud NAT gateway in the same region and attach it to the VPC.

    Why it's wrong here

    Cloud NAT is used for outbound internet access, not specifically for Google API access without external IPs. Private Google Access is the correct method.

  • Assign external IPs to the instances and create firewall rules to allow traffic to Google APIs.

    Why it's wrong here

    This defeats the requirement of not having external IPs and may introduce security risks.

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.

Trap categories for this question

  • Scenario analysis trap

    This is complex and unnecessary; Private Google Access is designed for this scenario.

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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

Visual reference

Inside (Private) PC-A 10.0.0.1 PC-B 10.0.0.2 NAT Router Outside (Public) 203.0.113.1 Inside Global Server PAT: many private IPs share one public IP via unique port numbers

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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FAQ

Questions learners often ask

What does this PCNE question test?

Implementing VPC Instances — This question tests Implementing VPC Instances — CIDR notation defines the prefix length..

What is the correct answer to this question?

The correct answer is: Configure the subnet to have Private Google Access enabled. Ensure the instances have the appropriate DNS resolution for private.googleapis.com. — Private Google Access enables instances without external IPs to reach Google APIs using internal IPs via the default internet gateway or VPC peering. Configuring a Private Google Access enabled subnet is the simplest and cheapest option, as it does not require NAT or additional instances.

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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Last reviewed: Jul 4, 2026

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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.