ANS-C01 Network Design Practice Question
A company is designing a VPC with a public subnet and a private subnet. The private subnet instances need to access the internet for software updates. Which TWO options allow outbound internet access while preventing inbound connections? (Choose two.)
⚠ Common exam trap
Candidates often confuse an Egress-Only Internet Gateway with a NAT Gateway, not realizing that the Egress-Only Internet Gateway is exclusively for IPv6 traffic and does not support IPv4, which is the typical protocol for software updates.
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
✓
NAT Gateway in the public subnet
A NAT Gateway in the public subnet allows instances in the private subnet to initiate outbound connections to the internet (e.g., for software updates) while preventing any unsolicited inbound connections from the internet. The NAT Gateway translates the private IP addresses of the instances to its own Elastic IP address, and because it does not maintain state for inbound traffic that was not initiated from within the VPC, it blocks all inbound connection attempts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
NAT Gateway in the public subnet
Why this is correct
Allows outbound IPv4 traffic from private subnet.
- ✓
Egress-only Internet Gateway
Why this is correct
Allows outbound IPv6 traffic only.
- ✗
Internet Gateway attached to the VPC
Why it's wrong here
Internet Gateway allows inbound traffic.
- ✗
AWS Site-to-Site VPN connection to on-premises
Why it's wrong here
VPN is for on-premises, not internet.
- ✗
VPC Peering connection to a VPC with internet access
Why it's wrong here
VPC Peering does not provide internet access.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.