- A
The private subnet route table does not have a route to the NAT Gateway for 0.0.0.0/0.
Why wrong: The web servers are in the public subnet, so the private subnet route table is irrelevant.
- B
The security group of the web servers is blocking outbound traffic to the internet.
Why wrong: Security groups are stateful and allow outbound traffic by default, so this is unlikely unless explicitly changed.
- C
The web servers are in a public subnet, but the route table for the public subnet points 0.0.0.0/0 to the NAT Gateway instead of the Internet Gateway.
Public subnets should route internet traffic to an Internet Gateway, not a NAT Gateway. The NAT Gateway is for private subnets.
- D
The NAT Gateway does not have a route to the Internet Gateway in its route table.
Why wrong: NAT Gateways are not associated with route tables; they are placed in a public subnet and automatically have a route to the IGW if the subnet route table directs 0.0.0.0/0 to the IGW.
Quick Answer
The correct answer is that the web servers are in a public subnet but the route table points 0.0.0.0/0 to a NAT Gateway instead of an Internet Gateway. This fails because public subnet internet access requires a direct route to an Internet Gateway (IGW); a NAT Gateway is designed for private subnets to initiate outbound traffic while remaining unreachable from the internet. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of the fundamental difference between NAT Gateway and IGW routing—a common trap is assuming a NAT Gateway in a public subnet provides internet access to instances in that same subnet, but the NAT Gateway itself needs an IGW route to function, creating a routing loop. Remember the memory tip: public subnets point to the IGW for direct internet access; private subnets point to the NAT Gateway for indirect access.
ANS-C01 Network Management and Operations Practice Question
This ANS-C01 practice question tests your understanding of network management and operations. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 deployed a web application in a VPC with public subnets for the web servers and private subnets for the database servers. The web servers need to access the internet for software updates. The network engineer configured a NAT Gateway in the public subnet and added a route in the private subnet route table pointing 0.0.0.0/0 to the NAT Gateway. However, the web servers cannot reach the internet. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 web servers are in a public subnet, but the route table for the public subnet points 0.0.0.0/0 to the NAT Gateway instead of the Internet Gateway.
Option C is correct because the web servers are deployed in a public subnet, which requires a route table entry pointing 0.0.0.0/0 to an Internet Gateway (IGW) for direct internet access. Instead, the engineer configured the route to point to a NAT Gateway, which is intended for private subnets. A public subnet must have a direct IGW route; using a NAT Gateway in a public subnet breaks outbound connectivity because the NAT Gateway itself relies on the IGW for internet access, but the web servers' traffic is sent to the NAT Gateway instead of the IGW, causing a routing loop or failure.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 private subnet route table does not have a route to the NAT Gateway for 0.0.0.0/0.
Why it's wrong here
The web servers are in the public subnet, so the private subnet route table is irrelevant.
- ✗
The security group of the web servers is blocking outbound traffic to the internet.
Why it's wrong here
Security groups are stateful and allow outbound traffic by default, so this is unlikely unless explicitly changed.
- ✓
The web servers are in a public subnet, but the route table for the public subnet points 0.0.0.0/0 to the NAT Gateway instead of the Internet Gateway.
Why this is correct
Public subnets should route internet traffic to an Internet Gateway, not a NAT Gateway. The NAT Gateway is for private subnets.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The NAT Gateway does not have a route to the Internet Gateway in its route table.
Why it's wrong here
NAT Gateways are not associated with route tables; they are placed in a public subnet and automatically have a route to the IGW if the subnet route table directs 0.0.0.0/0 to the IGW.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the purpose of a NAT Gateway (for private subnets) with an Internet Gateway (for public subnets), and assume that placing a NAT Gateway in a public subnet automatically provides internet access to instances in that subnet, when in fact the route table must point to the IGW for public subnets.
Detailed technical explanation
How to think about this question
In AWS, a public subnet is defined by having a route table entry that directs 0.0.0.0/0 to an Internet Gateway. A NAT Gateway is placed in a public subnet and uses the IGW for outbound traffic, but instances in a public subnet should use the IGW directly, not the NAT Gateway. If a public subnet's route table points to a NAT Gateway, traffic from instances will be sent to the NAT Gateway, which then tries to forward it to the IGW, but the NAT Gateway's own outbound traffic is already handled by its Elastic IP and the IGW; this misconfiguration can cause asymmetric routing or dropped packets because the NAT Gateway is not designed to forward traffic from instances in the same subnet back to the IGW.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Network Management and Operations — study guide chapter
Learn the concepts, then practise the questions
- →
Network Management and Operations practice questions
Targeted practice on this topic area only
- →
All ANS-C01 questions
1,705 questions across all exam domains
- →
AWS Certified Advanced Networking Specialty ANS-C01 study guide
Full concept coverage aligned to exam objectives
- →
ANS-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related ANS-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network Management and Operations practice questions
Practise ANS-C01 questions linked to Network Management and Operations.
Network Security, Compliance and Governance practice questions
Practise ANS-C01 questions linked to Network Security, Compliance and Governance.
Network Design practice questions
Practise ANS-C01 questions linked to Network Design.
Network Implementation practice questions
Practise ANS-C01 questions linked to Network Implementation.
ANS-C01 fundamentals practice questions
Practise ANS-C01 questions linked to ANS-C01 fundamentals.
ANS-C01 scenario practice questions
Practise ANS-C01 questions linked to ANS-C01 scenario.
ANS-C01 troubleshooting practice questions
Practise ANS-C01 questions linked to ANS-C01 troubleshooting.
Practice this exam
Start a free ANS-C01 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this ANS-C01 question test?
Network Management and Operations — This question tests Network Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The web servers are in a public subnet, but the route table for the public subnet points 0.0.0.0/0 to the NAT Gateway instead of the Internet Gateway. — Option C is correct because the web servers are deployed in a public subnet, which requires a route table entry pointing 0.0.0.0/0 to an Internet Gateway (IGW) for direct internet access. Instead, the engineer configured the route to point to a NAT Gateway, which is intended for private subnets. A public subnet must have a direct IGW route; using a NAT Gateway in a public subnet breaks outbound connectivity because the NAT Gateway itself relies on the IGW for internet access, but the web servers' traffic is sent to the NAT Gateway instead of the IGW, causing a routing loop or failure.
What should I do if I get this ANS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.