Quick Answer
The answer is an internet gateway attached to the VPC, multiple Availability Zones, and a NAT gateway in each AZ. These three components form the backbone of a highly available VPC design because they eliminate single points of failure at the network edge, the compute layer, and the outbound internet path. An internet gateway is a horizontally scaled, redundant service that provides inbound and outbound connectivity to the entire VPC, while deploying resources across multiple Availability Zones ensures application continuity if an entire zone fails. A NAT gateway in each AZ guarantees that instances in private subnets can reach the internet for updates or patches without relying on a single, fragile appliance. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this question tests your ability to distinguish between high-availability patterns and connectivity features—a common trap is confusing a single VPN connection or VPC peering with zone-level resilience. Memory tip: think of the three pillars of VPC HA—Edge (IGW), Spread (AZs), and Escape (NAT per AZ).
This ANS-C01 practice question tests your understanding of network design. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 designing a VPC for a web application that requires high availability. The application will be deployed across multiple Availability Zones. Which THREE components are essential for a highly available network design? (Choose THREE.)
Subnets in at least two Availability Zones
Provides AZ redundancy.
A single VPN connection to on-premises
Why wrong: Single point of failure.
A NAT gateway in each Availability Zone
Ensures outbound connectivity during AZ failure.
VPC peering with a backup VPC
Why wrong: Not essential for single VPC high availability.
An internet gateway attached to the VPC
Required for public internet access.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Subnets in at least two Availability Zones
Option A is correct: Multiple AZs ensure availability if one AZ fails. Option B is correct: An internet gateway provides internet access. Option D is correct: A NAT gateway in each AZ ensures outbound internet access even if one AZ fails. Option C is wrong because a single VPN connection is a single point of failure. Option E is wrong because VPC peering is for connecting VPCs, not for high availability within a VPC.
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
For each option: why learners choose it and why it is or isn't the right answer here.
Subnets in at least two Availability Zones
Why this is correct
Provides AZ redundancy.
Related concept
CIDR notation defines the prefix length.
A single VPN connection to on-premises
Why it's wrong here
Single point of failure.
A NAT gateway in each Availability Zone
Why this is correct
Ensures outbound connectivity during AZ failure.
Related concept
CIDR notation defines the prefix length.
VPC peering with a backup VPC
Why it's wrong here
Not essential for single VPC high availability.
An internet gateway attached to the VPC
Why this is correct
Required for public internet access.
Related concept
CIDR notation defines the prefix length.
Common exam traps
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
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.
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
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.
What to study next
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 Design — study guide chapter
Learn the concepts, then practise the questions
Network Design 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
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise ANS-C01 questions linked to Network Management and Operations.
Practise ANS-C01 questions linked to Network Security, Compliance and Governance.
Practise ANS-C01 questions linked to Network Design.
Practise ANS-C01 questions linked to Network Implementation.
Practise ANS-C01 questions linked to ANS-C01 fundamentals.
Practise ANS-C01 questions linked to ANS-C01 scenario.
Practise ANS-C01 questions linked to ANS-C01 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Network Design — This question tests Network Design — CIDR notation defines the prefix length..
The correct answer is: Subnets in at least two Availability Zones — Option A is correct: Multiple AZs ensure availability if one AZ fails. Option B is correct: An internet gateway provides internet access. Option D is correct: A NAT gateway in each AZ ensures outbound internet access even if one AZ fails. Option C is wrong because a single VPN connection is a single point of failure. Option E is wrong because VPC peering is for connecting VPCs, not for high availability within a VPC.
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.
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 →
Last reviewed: Jun 20, 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.