Quick Answer
The correct combination is a NAT gateway and an egress-only internet gateway. This pairing is required because a NAT gateway handles outbound IPv4 traffic from private instances, while an egress-only internet gateway provides a similar one-way path for IPv6 traffic, allowing instances to initiate outbound connections for updates without permitting inbound traffic. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of dual-stack private subnet internet access, specifically how to separate IPv4 and IPv6 egress paths. A common trap is confusing an internet gateway, which is designed for public subnets and allows bidirectional traffic, with the egress-only gateway that only supports outbound IPv6. Remember the memory tip: “NAT for 4, egress for 6” — each protocol gets its own dedicated outbound gateway to maintain privacy.
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 setting up a new VPC with both IPv4 and IPv6 support. They need to ensure that instances in a private subnet can access the Internet for software updates. Which combination of resources is required?
VPC endpoint and internet gateway
Why wrong: VPC endpoint is for specific AWS services, not general internet.
NAT gateway and egress-only internet gateway
NAT for IPv4, egress-only for IPv6.
NAT instance and internet gateway
Why wrong: NAT instance is not recommended; internet gateway not for private subnets.
Internet gateway and NAT gateway
Why wrong: Internet gateway is for public subnets; NAT gateway only for IPv4.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
NAT gateway and egress-only internet gateway
Option B is correct because a NAT gateway provides IPv4 internet access, and an egress-only internet gateway provides IPv6 internet access for private instances. Option A is wrong because internet gateway is for public subnets. Option C is wrong because NAT instance is outdated and more complex. Option D is wrong because VPC endpoint is for AWS services, not internet.
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.
VPC endpoint and internet gateway
Why it's wrong here
VPC endpoint is for specific AWS services, not general internet.
NAT gateway and egress-only internet gateway
NAT instance and internet gateway
Internet gateway and NAT gateway
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.
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FAQ
Network Implementation — This question tests Network Implementation — CIDR notation defines the prefix length..
The correct answer is: NAT gateway and egress-only internet gateway — Option B is correct because a NAT gateway provides IPv4 internet access, and an egress-only internet gateway provides IPv6 internet access for private instances. Option A is wrong because internet gateway is for public subnets. Option C is wrong because NAT instance is outdated and more complex. Option D is wrong because VPC endpoint is for AWS services, not internet.
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.
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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.
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