The answer is to use an HTTPS listener on the ALB and configure the target group with HTTPS. This works because the ALB terminates the client’s TLS connection at the listener and then establishes a separate, encrypted TLS connection to each EC2 instance in the target group, ensuring end-to-end encryption between the load balancer and the backend. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of how Application Load Balancers handle encryption at different layers, often appearing as a distractor where HTTP listeners or TCP listeners are offered as incorrect options. A common trap is assuming that security group rules alone can enforce encryption—they cannot, as they only control access, not data-in-transit protection. Remember the memory tip: “HTTPS all the way” means both the listener and the target group must use HTTPS for full encryption between ALB and EC2.
SCS-C02 Infrastructure Security Practice Question
This SCS-C02 practice question tests your understanding of infrastructure security. 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 runs a web application on EC2 instances behind an Application Load Balancer (ALB). The security team requires that all traffic between the ALB and EC2 instances be encrypted. Which configuration ensures this requirement is met?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use an HTTPS listener on the ALB and configure the target group with HTTPS.
Option D is correct because HTTPS listeners on the ALB terminate the client's TLS connection and establish a new TLS connection to the target group, ensuring encryption. Option A is wrong because HTTP does not encrypt traffic. Option B is wrong because security group rules do not enforce encryption. Option C is wrong because TCP listeners do not provide encryption.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Use an HTTPS listener on the ALB and configure the target group with HTTPS.
Configure security group inbound rules to allow only HTTPS traffic.
Why it's wrong here
Security groups only filter traffic, they do not enforce encryption.
✗
Use an HTTP listener on the ALB and HTTP on the target group.
Why it's wrong here
HTTP does not encrypt traffic between ALB and instances.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SCS-C02 NAT questions on configuration and troubleshooting.
Infrastructure Security — This question tests Infrastructure Security — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Use an HTTPS listener on the ALB and configure the target group with HTTPS. — Option D is correct because HTTPS listeners on the ALB terminate the client's TLS connection and establish a new TLS connection to the target group, ensuring encryption. Option A is wrong because HTTP does not encrypt traffic. Option B is wrong because security group rules do not enforce encryption. Option C is wrong because TCP listeners do not provide encryption.
What should I do if I get this SCS-C02 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SCS-C02 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is deploying a web application on EC2 instances behind an Application Load Balancer. The security team requires that all traffic between the ALB and the EC2 instances be encrypted. Which configuration should the engineer implement?
hard
A.Configure the ALB listener with HTTP protocol and the target group with HTTP protocol, then use a security group to restrict traffic.
B.Configure the ALB listener with HTTPS protocol and the target group with HTTP protocol.
C.Configure the ALB listener with TCP protocol and the target group with TCP protocol, then install SSL certificates on the EC2 instances.
✓ D.Configure the ALB listener with HTTPS protocol and the target group with HTTPS protocol, and install SSL certificates on the EC2 instances.
Why D: Option D is correct. To encrypt traffic between ALB and EC2, you must use HTTPS listeners on both sides: the ALB listener for frontend and the target group protocol for backend. Option A uses TCP, which is not encrypted. Option B only encrypts the frontend. Option C uses HTTP, not encrypted.
Last reviewed: Jun 20, 2026
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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.
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