- A
Place the Redis cluster in a public subnet and restrict access via security group.
Why wrong: Public subnet implies internet exposure, even with security groups.
- B
Place the Redis cluster in a private subnet and the EC2 instances in a private subnet, with a NAT Gateway for outbound traffic.
Why wrong: NAT Gateway is for internet access, not needed for VPC internal communication.
- C
Place the Redis cluster in a private subnet and the EC2 instances in a public subnet.
Why wrong: EC2 instances should be in private subnets for security.
- D
Place both the EC2 instances and the Redis cluster in private subnets with appropriate security groups.
Both in private subnets, security groups allow traffic from EC2 to Redis.
Question 416 of 1,705
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 is running a web application on EC2 instances behind an Application Load Balancer (ALB) in a VPC. The application needs to store session state in an ElastiCache Redis cluster. The Redis cluster should not be accessible from the internet. Which network design should be used?
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
✓
Place both the EC2 instances and the Redis cluster in private subnets with appropriate security groups.
Option D is correct because placing both the EC2 instances and the ElastiCache Redis cluster in private subnets ensures that the Redis cluster is not accessible from the internet, meeting the security requirement. The EC2 instances can communicate with the Redis cluster within the same VPC using private IP addresses, and security groups can be used to restrict traffic to only the necessary ports (e.g., TCP 6379 for Redis) from the EC2 instances' security group. This design avoids exposing the Redis cluster to any public network, aligning with best practices for internal caching layers.
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.
- ✗
Place the Redis cluster in a public subnet and restrict access via security group.
Why it's wrong here
Public subnet implies internet exposure, even with security groups.
- ✗
Place the Redis cluster in a private subnet and the EC2 instances in a private subnet, with a NAT Gateway for outbound traffic.
- ✗
Place the Redis cluster in a private subnet and the EC2 instances in a public subnet.
Why it's wrong here
EC2 instances should be in private subnets for security.
- ✓
Place both the EC2 instances and the Redis cluster in private subnets with appropriate security groups.
Why this is correct
Both in private subnets, security groups allow traffic from EC2 to Redis.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think a NAT Gateway is required for EC2 instances in private subnets to communicate with ElastiCache, but in reality, VPC internal traffic uses private IPs and does not require a NAT Gateway, which is only for outbound internet access.
Detailed technical explanation
How to think about this question
Under the hood, ElastiCache Redis clusters in a VPC use private IP addresses and rely on security groups for network access control; the default Redis port is TCP 6379, and communication between EC2 and Redis occurs over this port without encryption unless TLS is enabled (which requires additional configuration). In a real-world scenario, if the EC2 instances are in an Auto Scaling group behind an ALB, placing them in private subnets with a NAT Gateway for outbound updates (e.g., to download patches) is common, but the NAT Gateway is not needed for Redis access because Redis is within the same VPC. A subtle behavior is that ElastiCache clusters cannot be placed in a public subnet directly; they must be in private subnets, making options A and C technically invalid from an AWS architecture standpoint.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
Visual reference
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
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.
- →
Network Implementation — study guide chapter
Learn the concepts, then practise the questions
- →
Network Implementation practice questions
Targeted practice on this topic area only
- →
All ANS-C01 questions
1,705 questions across all exam domains
- →
AWS Certified Advanced Networking Specialty ANS-C01 study guide
Full concept coverage aligned to exam objectives
- →
ANS-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related ANS-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network Management and Operations practice questions
Practise ANS-C01 questions linked to Network Management and Operations.
Network Security, Compliance and Governance practice questions
Practise ANS-C01 questions linked to Network Security, Compliance and Governance.
Network Design practice questions
Practise ANS-C01 questions linked to Network Design.
Network Implementation practice questions
Practise ANS-C01 questions linked to Network Implementation.
ANS-C01 fundamentals practice questions
Practise ANS-C01 questions linked to ANS-C01 fundamentals.
ANS-C01 scenario practice questions
Practise ANS-C01 questions linked to ANS-C01 scenario.
ANS-C01 troubleshooting practice questions
Practise ANS-C01 questions linked to ANS-C01 troubleshooting.
Practice this exam
Start a free ANS-C01 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 ANS-C01 question test?
Network Implementation — This question tests Network Implementation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Place both the EC2 instances and the Redis cluster in private subnets with appropriate security groups. — Option D is correct because placing both the EC2 instances and the ElastiCache Redis cluster in private subnets ensures that the Redis cluster is not accessible from the internet, meeting the security requirement. The EC2 instances can communicate with the Redis cluster within the same VPC using private IP addresses, and security groups can be used to restrict traffic to only the necessary ports (e.g., TCP 6379 for Redis) from the EC2 instances' security group. This design avoids exposing the Redis cluster to any public network, aligning with best practices for internal caching layers.
What should I do if I get this ANS-C01 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 ANS-C01 practice questions
- A financial services company has a VPC with a public subnet and a private subnet. EC2 instances in the private subnet ne…
- A company is designing a network security architecture for a multi-account environment using AWS Transit Gateway. The se…
- A company is using AWS Direct Connect to connect its on-premises network to AWS. The company wants to encrypt all traffi…
- A company uses AWS Transit Gateway to connect multiple VPCs and on-premises networks via AWS Site-to-Site VPN. The secur…
- A company runs a web application on EC2 instances behind an Application Load Balancer (ALB). The application must be acc…
- A global e-commerce company uses a hub-and-spoke network topology with a transit VPC in us-east-1. Each spoke VPC has an…
Last reviewed: Jul 4, 2026
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.