The answer is to use AWS Transit Gateway with a VPN attachment between the VPCs, because VPC Peering itself does not support any form of encryption for traffic in transit. While VPC Peering connects networks privately using the AWS backbone, the data plane traffic flows unencrypted, so you must overlay an IPsec VPN tunnel to achieve encryption. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this question tests your understanding that VPC Peering is a Layer 3 connection with no native encryption, and the common trap is assuming a peering connection is automatically secure. A frequent distractor is Direct Connect, which also does not encrypt by default unless you add a VPN or MACsec. Remember the key distinction: peering provides private routing, not encryption; to encrypt traffic between VPCs, you always need a VPN overlay, and Transit Gateway simplifies managing those tunnels at scale. Memory tip: “Peering is private, but not protected—VPN adds the shield.”
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 multiple subnets that are peered with another VPC using a VPC Peering connection. They want to ensure that traffic between the two VPCs is encrypted. What should they do?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use AWS Transit Gateway with a VPN attachment between the VPCs.
VPC Peering does not support encryption of traffic. To add encryption, you can deploy a VPN connection between the VPCs, or use an overlay solution. Option A (Transit Gateway with VPN) is a valid approach. Option B (Internet Gateway) would expose traffic to the internet. Option C (NACL) does not encrypt. Option D (Direct Connect) does not encrypt by default.
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 network ACLs to enforce encryption.
Why it's wrong here
NACLs are stateless firewalls and do not provide encryption.
✓
Use AWS Transit Gateway with a VPN attachment between the VPCs.
Why this is correct
Transit Gateway with VPN can provide encrypted connectivity between VPCs.
Direct Connect public VIF does not encrypt traffic; encryption would need to be implemented at the application layer.
✗
Enable encryption on the VPC Peering connection using a security group.
Why it's wrong here
VPC Peering does not support encryption; security groups control access but do not encrypt.
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.
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: Use AWS Transit Gateway with a VPN attachment between the VPCs. — VPC Peering does not support encryption of traffic. To add encryption, you can deploy a VPN connection between the VPCs, or use an overlay solution. Option A (Transit Gateway with VPN) is a valid approach. Option B (Internet Gateway) would expose traffic to the internet. Option C (NACL) does not encrypt. Option D (Direct Connect) does not encrypt by default.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.