- A
Verify that the VPN tunnel status shows as UP on both sides.
Why wrong: While tunnel status is important, the issue could be due to route propagation or association problems, not tunnel status alone.
- B
Enable VPC Flow Logs on VPC A to verify traffic reaching the transit gateway.
Why wrong: VPC Flow Logs capture traffic at the VPC level, not inside the transit gateway, so they won't show routing decisions within the transit gateway.
- C
In the transit gateway route table, verify that the VPN attachment is correctly associated and that the 10.0.0.0/8 route is propagated and has the correct attachment.
This directly checks whether the transit gateway is correctly routing traffic to the VPN attachment for the on-premises CIDR.
- D
Check the security group rules on the EC2 instances in VPC A for outbound traffic.
Why wrong: Security groups control inbound/outbound traffic to instances, but the issue is about network routing through the transit gateway.
Quick Answer
The correct first step is to verify that the VPN attachment is correctly associated with the transit gateway route table and that the 10.0.0.0/8 route is propagated and points to the correct attachment. This is because intermittent connectivity issues often stem from a misconfigured route table rather than a failed VPN tunnel; if the route is missing or associated with the wrong attachment, traffic from VPC A to the on-premises network will be dropped even when the VPN itself is healthy. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of Transit Gateway route table troubleshooting as a foundational diagnostic step, with a common trap being that engineers jump to checking VPN tunnel status or VPC subnet routes first. Remember that the transit gateway route table is the central decision point for all inter-network traffic, so always start there. A useful memory tip is "Route before tunnel" — verify the route table association and propagation before investigating the VPN tunnel itself.
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 uses AWS Transit Gateway to connect multiple VPCs and on-premises networks via VPN. Network engineers report intermittent connectivity issues between VPC A and the on-premises network. The transit gateway route table shows the on-premises CIDR (10.0.0.0/8) propagated from the VPN attachment. VPC A has a subnet route pointing to the transit gateway for 10.0.0.0/8. Which step should the engineer take FIRST to diagnose the issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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
In the transit gateway route table, verify that the VPN attachment is correctly associated and that the 10.0.0.0/8 route is propagated and has the correct attachment.
Option C is correct because the first diagnostic step for intermittent connectivity through a transit gateway is to verify the route table configuration. The engineer must confirm that the VPN attachment is correctly associated with the transit gateway route table and that the 10.0.0.0/8 route is propagated from the VPN attachment, as a missing or misassociated route would cause traffic to be dropped even if the VPN tunnel is up.
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.
- ✗
Verify that the VPN tunnel status shows as UP on both sides.
Why it's wrong here
While tunnel status is important, the issue could be due to route propagation or association problems, not tunnel status alone.
- ✗
Enable VPC Flow Logs on VPC A to verify traffic reaching the transit gateway.
Why it's wrong here
VPC Flow Logs capture traffic at the VPC level, not inside the transit gateway, so they won't show routing decisions within the transit gateway.
- ✓
In the transit gateway route table, verify that the VPN attachment is correctly associated and that the 10.0.0.0/8 route is propagated and has the correct attachment.
- ✗
Check the security group rules on the EC2 instances in VPC A for outbound traffic.
Why it's wrong here
Security groups control inbound/outbound traffic to instances, but the issue is about network routing through the transit gateway.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often jump to checking the VPN tunnel status (Option A) first, assuming the tunnel is the root cause, but the question specifically describes intermittent connectivity that is more likely due to a routing misconfiguration in the transit gateway route table rather than a tunnel flap.
Trap categories for this question
Command / output trap
VPC Flow Logs capture traffic at the VPC level, not inside the transit gateway, so they won't show routing decisions within the transit gateway.
Detailed technical explanation
How to think about this question
AWS Transit Gateway uses route tables to determine how to forward traffic between attachments; a propagated route from a VPN attachment must be present and the attachment must be associated with the correct route table. Intermittent issues can arise from route propagation delays or misconfiguration of the VPN attachment association, which can be verified by inspecting the transit gateway route table for the 10.0.0.0/8 entry and its target attachment ID.
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: In the transit gateway route table, verify that the VPN attachment is correctly associated and that the 10.0.0.0/8 route is propagated and has the correct attachment. — Option C is correct because the first diagnostic step for intermittent connectivity through a transit gateway is to verify the route table configuration. The engineer must confirm that the VPN attachment is correctly associated with the transit gateway route table and that the 10.0.0.0/8 route is propagated from the VPN attachment, as a missing or misassociated route would cause traffic to be dropped even if the VPN tunnel is up.
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: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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 →
Same concept, more angles
3 more ways this is tested on ANS-C01
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 uses AWS Transit Gateway to connect multiple VPCs and on-premises networks. The network team notices that traffic between two VPCs is taking a suboptimal path, going through the on-premises network instead of staying within AWS. What is the most likely cause?
hard- ✓ A.The Transit Gateway route table has a propagated route from the on-premises network with a longer prefix
- B.The VPCs are also peered directly, creating a conflict
- C.VPC Flow Logs are enabled, causing latency
- D.Security groups are blocking direct traffic between VPCs
Why A: Option D is correct because Transit Gateway route propagation from on-premises (VPN or Direct Connect) can advertise more specific routes that override the local VPC routes. Option A is wrong because VPC peering is not used with Transit Gateway. Option B is wrong because security groups do not affect routing. Option C is wrong because flow logs are for monitoring, not routing decisions.
Variation 2. A company uses AWS Transit Gateway to connect multiple VPCs and on-premises networks via AWS Direct Connect. The network team notices that traffic from an on-premises data center to a VPC is intermittently dropping. CloudWatch metrics show no errors on the Direct Connect virtual interface. What is the most likely cause of the intermittent drops?
medium- A.Latency spikes on the Direct Connect link due to AWS VPN backup path
- B.MTU mismatch causing packet fragmentation for jumbo frames
- C.BGP keepalive timer mismatch between the on-premises router and the Direct Connect router
- ✓ D.Asymmetric routing due to missing or incorrect route propagation in Transit Gateway route tables
Why D: Option B is correct because asymmetric routing can cause packet drops when Transit Gateway does not have a route back to the source. Option A is wrong because BGP timers would cause sustained loss. Option C is wrong because MTU mismatch typically causes packet loss only for large packets. Option D is wrong because VPN would not be in path if Direct Connect is used.
Variation 3. A company uses AWS Transit Gateway to connect multiple VPCs and on-premises networks. After adding a new VPC attachment, traffic from the on-premises network cannot reach the new VPC. The on-premises BGP route table shows the prefixes of the new VPC as received. What should the engineer check?
medium- A.Verify that the on-premises router is advertising the correct prefix to AWS.
- B.Verify that the new VPC has a route to the Transit Gateway in its route table.
- ✓ C.Verify that the new VPC attachment is associated with the Transit Gateway route table that has the on-premises routes.
- D.Verify that the new VPC's DNS resolution is enabled.
Why C: Option B is correct because Transit Gateway route tables control inter-VPC and on-premises connectivity; the new VPC attachment must be associated with the correct route table. Option A is wrong because the on-premises already has the routes. Option C is wrong because there is no implied propagation. Option D is wrong because subdomain is irrelevant.
Keep practising
More ANS-C01 practice questions
- A company is designing a network security architecture for a multi-account environment using AWS Transit Gateway. The se…
- A company is using AWS Direct Connect to connect its on-premises network to AWS. The company wants to encrypt all traffi…
- A company uses AWS Transit Gateway to connect multiple VPCs and on-premises networks via AWS Site-to-Site VPN. The secur…
- A global e-commerce company uses a hub-and-spoke network topology with a transit VPC in us-east-1. Each spoke VPC has an…
- A company is designing a multi-VPC architecture in the same region. The VPCs need to communicate with each other using p…
- A company is deploying an application that requires low-latency communication between EC2 instances in two different AWS…
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.