- A
Configure network ACLs to allow traffic
Why wrong: NACLs do not encrypt.
- B
Use VPC Peering
Why wrong: VPC Peering does not encrypt traffic.
- C
Set up an IPsec VPN between the instances
IPsec encrypts all IP traffic between the endpoints.
- D
Configure security groups to allow traffic
Why wrong: Security groups only filter, not encrypt.
Question 599 of 1,748
SCS-C02 Infrastructure Security Practice Question
This SCS-C02 practice question tests your understanding of infrastructure security. 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 security engineer needs to ensure that all traffic between two EC2 instances in different subnets is encrypted in transit. What is the most secure and efficient solution?
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
✓
Set up an IPsec VPN between the instances
Option C is correct because an IPsec VPN between the two EC2 instances provides end-to-end encryption of all traffic at the network layer, regardless of the application protocol. This ensures that data in transit between the instances is encrypted using IPsec (ESP/AH), which is the most secure and efficient solution for encrypting traffic between two specific instances in different subnets without relying on the underlying network infrastructure.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 allow traffic
Why it's wrong here
NACLs do not encrypt.
- ✗
Use VPC Peering
Why it's wrong here
VPC Peering does not encrypt traffic.
- ✓
Set up an IPsec VPN between the instances
Why this is correct
IPsec encrypts all IP traffic between the endpoints.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Configure security groups to allow traffic
Why it's wrong here
Security groups only filter, not encrypt.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse network-layer connectivity solutions (like VPC Peering or security groups) with encryption mechanisms, assuming that routing traffic through AWS's private network or allowing traffic via security groups inherently encrypts the data, when in fact neither provides encryption in transit.
Detailed technical explanation
How to think about this question
IPsec operates in either transport mode (encrypting only the payload) or tunnel mode (encrypting the entire IP packet), and when configured between two EC2 instances, it typically uses IKEv2 for key exchange and ESP for encryption (e.g., AES-256-GCM). A real-world scenario where this matters is when compliance requirements (e.g., PCI DSS, HIPAA) mandate encryption of data in transit between application tiers, and using IPsec avoids the overhead of application-level encryption while providing strong cryptographic protection at the network layer.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Visual reference
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Infrastructure Security — study guide chapter
Learn the concepts, then practise the questions
- →
Infrastructure Security practice questions
Targeted practice on this topic area only
- →
All SCS-C02 questions
1,748 questions across all exam domains
- →
AWS Certified Security Specialty SCS-C02 study guide
Full concept coverage aligned to exam objectives
- →
SCS-C02 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related SCS-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Threat Detection and Incident Response practice questions
Practise SCS-C02 questions linked to Threat Detection and Incident Response.
Security Logging and Monitoring practice questions
Practise SCS-C02 questions linked to Security Logging and Monitoring.
Identity and Access Management practice questions
Practise SCS-C02 questions linked to Identity and Access Management.
Management and Security Governance practice questions
Practise SCS-C02 questions linked to Management and Security Governance.
Infrastructure Security practice questions
Practise SCS-C02 questions linked to Infrastructure Security.
Data Protection practice questions
Practise SCS-C02 questions linked to Data Protection.
SCS-C02 fundamentals practice questions
Practise SCS-C02 questions linked to SCS-C02 fundamentals.
SCS-C02 scenario practice questions
Practise SCS-C02 questions linked to SCS-C02 scenario.
SCS-C02 troubleshooting practice questions
Practise SCS-C02 questions linked to SCS-C02 troubleshooting.
Practice this exam
Start a free SCS-C02 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this SCS-C02 question test?
Infrastructure Security — This question tests Infrastructure Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set up an IPsec VPN between the instances — Option C is correct because an IPsec VPN between the two EC2 instances provides end-to-end encryption of all traffic at the network layer, regardless of the application protocol. This ensures that data in transit between the instances is encrypted using IPsec (ESP/AH), which is the most secure and efficient solution for encrypting traffic between two specific instances in different subnets without relying on the underlying network infrastructure.
What should I do if I get this SCS-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
Keep practising
More SCS-C02 practice questions
- A company uses AWS Organizations with multiple accounts. The security team wants to enforce that all Amazon S3 buckets a…
- A company is designing a multi-tier web application on AWS. The web tier must be accessible from the internet, but the a…
- A company is migrating a legacy application to AWS. The application requires two-way communication between the web serve…
- A security engineer is troubleshooting connectivity issues between an Amazon EC2 instance in a VPC and an on-premises se…
- A security engineer is reviewing the SQS queue policy shown in the exhibit. The queue is subscribed to an SNS topic in t…
- A company uses AWS Organizations with multiple accounts. The security team wants to ensure that all IAM users in the pro…
Last reviewed: Jul 4, 2026
This SCS-C02 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 SCS-C02 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.