ANS-C01 Network Implementation Practice Question
A company is deploying a new VPC with public and private subnets. The company wants to ensure that EC2 instances in the private subnet can access the internet for software updates. The instances do not need to be accessible from the internet. The network engineer has created a NAT gateway in the public subnet and added a route in the private subnet's route table pointing 0.0.0.0/0 to the NAT gateway. However, instances in the private subnet cannot reach the internet. The NAT gateway is in the 'available' state. What is the MOST likely cause?
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
✓
The NAT gateway does not have an Elastic IP address associated.
An Elastic IP must be associated with the NAT gateway for it to work. Option A is incorrect because the NAT gateway is already in a public subnet. Option C is incorrect because the route is present. Option D is incorrect because security groups do not block outbound traffic to internet by default.
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 not in a public subnet.
Why it's wrong here
Stem says it is in a public subnet.
- ✓
The NAT gateway does not have an Elastic IP address associated.
Why this is correct
NAT gateway requires an EIP for internet access.
- ✗
The private subnet's route table does not have a default route to the NAT gateway.
Why it's wrong here
Stem says the route is present.
- ✗
The security group of the EC2 instances blocks outbound traffic.
Why it's wrong here
Default security group allows all outbound.
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JA
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.