Quick Answer
The answer is a NAT Gateway deployed in a public subnet. This is the correct choice because a NAT Gateway is a fully managed AWS service that enables instances in a private subnet to initiate outbound traffic to the internet for tasks like software updates, while preventing any unsolicited inbound connections. Unlike a NAT instance, which you must manage and patch yourself, the NAT Gateway is automatically scaled and highly available within an Availability Zone. For the AWS Certified Security Specialty SCS-C02 exam, this question tests your understanding of secure outbound connectivity patterns and the distinction between managed and unmanaged services. A common trap is confusing a NAT Gateway with a NAT instance or an Internet Gateway—remember that an Internet Gateway is for public subnets only, and a NAT instance is not managed by AWS. Memory tip: think “NAT Gateway = managed outbound only” and “Internet Gateway = inbound and outbound for public subnets.”
This SCS-C02 practice question tests your understanding of infrastructure security. 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. The private subnets need to access the internet for software updates. Which AWS service provides a managed, highly available, and scalable solution for this requirement?
NAT instance in a public subnet
Why wrong: NAT instance is a single EC2, not managed or highly available by default.
Internet Gateway attached to the VPC
Why wrong: Internet Gateway enables inbound/outbound for public subnets only.
NAT Gateway in a public subnet
NAT Gateway is managed, scalable, and highly available.
AWS Site-to-Site VPN connection
Why wrong: VPN connects to on-premises, not internet.
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 in a public subnet
Option B is correct because a NAT Gateway provides outbound internet access for instances in private subnets and is managed by AWS. Option A is wrong because a NAT instance is not managed. Option C is wrong because an Internet Gateway is used for public subnets. Option D is wrong because a VPN connection is for hybrid networking, not internet access.
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.
NAT instance in a public subnet
Why it's wrong here
NAT instance is a single EC2, not managed or highly available by default.
Internet Gateway attached to the VPC
Why it's wrong here
Internet Gateway enables inbound/outbound for public subnets only.
NAT Gateway in a public subnet
AWS Site-to-Site VPN connection
Why it's wrong here
VPN connects to on-premises, not internet.
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 SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
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FAQ
Infrastructure Security — This question tests Infrastructure Security — CIDR notation defines the prefix length..
The correct answer is: NAT Gateway in a public subnet — Option B is correct because a NAT Gateway provides outbound internet access for instances in private subnets and is managed by AWS. Option A is wrong because a NAT instance is not managed. Option C is wrong because an Internet Gateway is used for public subnets. Option D is wrong because a VPN connection is for hybrid networking, not internet access.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
CIDR notation defines the prefix length.
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Same concept, more angles
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 has a VPC with a public subnet and a private subnet. An EC2 instance in the private subnet needs to download patches from the internet. Which AWS service should be used to allow this without assigning a public IP address to the instance?
easyWhy C: Option C is correct because a NAT Gateway allows instances in a private subnet to connect to the internet while preventing inbound traffic from the internet. Option A is wrong because an Internet Gateway alone does not allow outbound-only for private instances. Option B is wrong because a VPN connection is for hybrid connectivity, not internet access. Option D is wrong because a VPC Endpoint is for private access to AWS services.
Variation 2. A company has a VPC with public and private subnets. The private subnets need to access the internet for software updates. Which component should be added to the VPC to enable this?
easyWhy D: The correct answer is A because a NAT gateway allows instances in private subnets to initiate outbound traffic to the internet while preventing inbound traffic from the internet. Option B is wrong because an internet gateway is for public subnets. Option C is wrong because a VPC peering connects VPCs. Option D is wrong because a VPN connection is for hybrid connectivity.
Last reviewed: Jun 20, 2026
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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