Question 1,384 of 1,705
Network ImplementationhardMultiple ChoiceObjective-mapped

Quick Answer

The answer is that traffic to the on-premises server at 10.0.0.5 stays local within the VPC. This occurs because the VPC’s implicit local route for its CIDR block 10.0.0.0/16 is a more specific prefix than the VPN route for 10.0.0.0/8, and AWS routing always applies the longest prefix match to determine precedence. Even though the VPN route covers the destination IP, the local VPC route wins because /16 is a longer match than /8. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of how route priority works when on-premises IPs fall within the VPC CIDR—a common trap is assuming a VPN or Direct Connect route will override local traffic. Remember the memory tip: “Local always wins inside your VPC block; a wider net cannot catch a closer fish.”

ANS-C01 Network Implementation Practice Question

This ANS-C01 practice question tests your understanding of network implementation. 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 has a VPC with a CIDR block of 10.0.0.0/16. The VPC has three subnets: 10.0.1.0/24, 10.0.2.0/24, and 10.0.3.0/24. An EC2 instance in subnet 10.0.1.0/24 needs to send traffic to an on-premises server at 10.0.0.5/32 via a VPN connection. The VPC route table has a route to the VPN gateway for 10.0.0.0/8. What is the expected behavior?

Question 1hardmultiple choice
Read the full VPN explanation →

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

Traffic to 10.0.0.5 stays within the VPC.

Option C is correct because the VPC has a more specific route (10.0.0.0/16) for local traffic, which takes precedence over the VPN route (10.0.0.0/8) due to longest prefix match. Traffic from the EC2 instance to 10.0.0.5 is within the VPC CIDR, so it stays local.

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.

  • Traffic to 10.0.0.5 is sent to the internet gateway.

    Why it's wrong here

    No route to IGW for 10.0.0.5.

  • Traffic to 10.0.0.5 is routed through the VPN gateway.

    Why it's wrong here

    The local route is more specific.

  • Traffic to 10.0.0.5 stays within the VPC.

    Why this is correct

    The VPC's local route matches 10.0.0.5.

    Related concept

    CIDR notation defines the prefix length.

  • Traffic to 10.0.0.5 is dropped because there is no matching route.

    Why it's wrong here

    There is a local route.

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 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 ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.

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FAQ

Questions learners often ask

What does this ANS-C01 question test?

Network Implementation — This question tests Network Implementation — CIDR notation defines the prefix length..

What is the correct answer to this question?

The correct answer is: Traffic to 10.0.0.5 stays within the VPC. — Option C is correct because the VPC has a more specific route (10.0.0.0/16) for local traffic, which takes precedence over the VPN route (10.0.0.0/8) due to longest prefix match. Traffic from the EC2 instance to 10.0.0.5 is within the VPC CIDR, so it stays local.

What should I do if I get this ANS-C01 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 ANS-C01 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: Jun 20, 2026

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This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.