← ANS-C01·Amazon Web Services

Question 623 of 1,705

Network Implementation →hardMultiple ChoiceObjective-mapped

ANS-C01 Network Implementation Practice Question

This ANS-C01 practice question tests your understanding of network implementation. 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 Direct Connect connection with a private VIF to a VPC. The on-premises network uses BGP to advertise a specific prefix (10.0.0.0/16) to AWS. The VPC CIDR is 10.0.0.0/16. The company wants to ensure that traffic from the VPC to on-premises uses the Direct Connect connection. However, traffic is going over the internet instead. 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.

A
The on-premises BGP ASN is prepended, causing the route to be less preferred.
Why wrong: AS path length does not override the local route.
B
The on-premises prefix is less specific than the VPC CIDR, so the VPC route takes precedence.
Why wrong: Actually, more specific routes are preferred, but the local route for exact match is always preferred.
C
The VPC CIDR overlaps with the on-premises prefix, and the local route in the VPC route table takes precedence.
Overlapping CIDRs cause the local route to be used, ignoring Direct Connect.
D
The BGP route is not being propagated into the VPC route table.
Why wrong: If the VPC CIDR overlaps, the local route wins regardless of propagation.

Full breakdown with real-world context →

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 VPC CIDR overlaps with the on-premises prefix, and the local route in the VPC route table takes precedence.

When a VPC CIDR (10.0.0.0/16) exactly matches a prefix advertised via Direct Connect (10.0.0.0/16), the VPC's local route (which is implicitly created for the VPC CIDR) takes precedence over any propagated BGP route. This is because AWS route tables prioritize the most specific matching route, and when prefixes are identical, the local route is preferred over static or propagated routes. As a result, traffic destined for 10.0.0.0/16 stays within the VPC instead of being sent over the Direct Connect connection.

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 on-premises BGP ASN is prepended, causing the route to be less preferred.
Why it's wrong here
AS path length does not override the local route.
✗
The on-premises prefix is less specific than the VPC CIDR, so the VPC route takes precedence.
Why it's wrong here
Actually, more specific routes are preferred, but the local route for exact match is always preferred.
✓
The VPC CIDR overlaps with the on-premises prefix, and the local route in the VPC route table takes precedence.
Why this is correct
Overlapping CIDRs cause the local route to be used, ignoring Direct Connect.
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 BGP route is not being propagated into the VPC route table.
Why it's wrong here
If the VPC CIDR overlaps, the local route wins regardless of propagation.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The ANS-C01 exam often tests the misconception that BGP propagated routes can override the VPC local route when prefixes are identical, but the trap here is that AWS always prioritizes the local route for exact CIDR matches, regardless of BGP attributes or propagation status.

Detailed technical explanation

How to think about this question

AWS VPC route tables have an implicit local route for the VPC CIDR that cannot be deleted or overridden by any other route, including propagated BGP routes or static routes, when the destination prefix is identical. This behavior is defined by AWS's longest prefix match rule, where the local route is always preferred for exact matches. In real-world scenarios, overlapping CIDRs between on-premises and AWS are a common misconfiguration that forces traffic to stay within the VPC, often requiring network address translation (NAT) or subdividing CIDRs to avoid overlap.

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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.

Visual reference

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.

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.

10 questions 20 questions 30 questions 50 questions Timed 30

ANS-C01 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this ANS-C01 question test?

Network Implementation — This question tests Network Implementation — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The VPC CIDR overlaps with the on-premises prefix, and the local route in the VPC route table takes precedence. — When a VPC CIDR (10.0.0.0/16) exactly matches a prefix advertised via Direct Connect (10.0.0.0/16), the VPC's local route (which is implicitly created for the VPC CIDR) takes precedence over any propagated BGP route. This is because AWS route tables prioritize the most specific matching route, and when prefixes are identical, the local route is preferred over static or propagated routes. As a result, traffic destined for 10.0.0.0/16 stays within the VPC instead of being sent over the Direct Connect connection.

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

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.

Loading comments…

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.