- A
The NAT gateway is deployed in a private subnet
Why wrong: NAT gateway must be in a public subnet.
- B
A security group attached to the NAT gateway
Why wrong: NAT gateways do not support security groups.
- C
A route in the public subnet's route table to an internet gateway
The NAT gateway must be in a public subnet with internet access.
- D
A network ACL attached to the NAT gateway's subnet that allows inbound traffic from the internet
Why wrong: NAT gateway only initiates outbound traffic; inbound from internet is not required.
- E
An Elastic IP address assigned to the NAT gateway
NAT gateway needs an Elastic IP to translate private IPs to a public IP.
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 has a VPC with public and private subnets. They have a NAT gateway in a public subnet for outbound internet access from private instances. Which TWO of the following are required for the NAT gateway to function correctly?
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
A route in the public subnet's route table to an internet gateway
Option A is required because the NAT gateway needs an Elastic IP for outbound traffic. Option B is required because the public subnet must have a route to an internet gateway. Option C is not required because security groups are not attached to NAT gateways. Option D is not required because NAT gateways are not assigned to private subnets. Option E is not required because NAT gateways do not use NACLs.
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
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The NAT gateway is deployed in a private subnet
- ✗
A security group attached to the NAT gateway
Why it's wrong here
NAT gateways do not support security groups.
- ✓
A route in the public subnet's route table to an internet gateway
- ✗
A network ACL attached to the NAT gateway's subnet that allows inbound traffic from the internet
- ✓
An Elastic IP address assigned to the NAT gateway
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
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
How to think about this question
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.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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
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.
What to study next
Got this wrong? Here's your next step.
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
Questions learners often ask
What does this ANS-C01 question test?
Network Implementation — This question tests Network Implementation — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: A route in the public subnet's route table to an internet gateway — Option A is required because the NAT gateway needs an Elastic IP for outbound traffic. Option B is required because the public subnet must have a route to an internet gateway. Option C is not required because security groups are not attached to NAT gateways. Option D is not required because NAT gateways are not assigned to private subnets. Option E is not required because NAT gateways do not use NACLs.
What should I do if I get this ANS-C01 question wrong?
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.
What is the key concept behind this question?
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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