Question 1,638 of 1,705
Network ImplementationmediumMultiple ChoiceObjective-mapped

ANS-C01 Network Implementation Practice Question

This ANS-C01 practice question tests your understanding of network implementation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.

Exhibit

Refer to the exhibit.

CloudFormation snippet:
Resources:
  MyTransitGateway:
    Type: AWS::EC2::TransitGateway
    Properties:
      AmazonSideAsn: 64512
      AutoAcceptSharedAttachments: disable
      DefaultRouteTableAssociation: enable
      DefaultRouteTablePropagation: enable
      DnsSupport: enable
      VpnEcmpSupport: enable
  MyVpcAttachment:
    Type: AWS::EC2::TransitGatewayAttachment
    Properties:
      SubnetIds:
        - subnet-abc
        - subnet-def
      TransitGatewayId: !Ref MyTransitGateway
      VpcId: vpc-12345

Refer to the exhibit. After deploying this CloudFormation stack, the VPC is attached to the transit gateway. However, routes are not being propagated to the transit gateway route table. 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.

Exhibit

Refer to the exhibit.

CloudFormation snippet:
Resources:
  MyTransitGateway:
    Type: AWS::EC2::TransitGateway
    Properties:
      AmazonSideAsn: 64512
      AutoAcceptSharedAttachments: disable
      DefaultRouteTableAssociation: enable
      DefaultRouteTablePropagation: enable
      DnsSupport: enable
      VpnEcmpSupport: enable
  MyVpcAttachment:
    Type: AWS::EC2::TransitGatewayAttachment
    Properties:
      SubnetIds:
        - subnet-abc
        - subnet-def
      TransitGatewayId: !Ref MyTransitGateway
      VpcId: vpc-12345

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 transit gateway route table propagation is not configured.

Option B is correct because the exhibit shows a transit gateway route table attached to the VPC, but no propagation is configured. Without explicit propagation, the VPC attachment's CIDR blocks are not automatically added to the transit gateway route table. The CloudFormation resource AWS::EC2::TransitGatewayRouteTablePropagation must be declared to enable route propagation from the VPC attachment into the transit gateway route table.

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 VPC attachment is not in the 'available' state.

    Why it's wrong here

    The attachment would fail if not available.

  • The transit gateway route table propagation is not configured.

    Why this is correct

    DefaultRouteTablePropagation enables automatic propagation, but the attachment does not explicitly propagate.

    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.

  • VPN ECMP support is enabled, preventing propagation.

    Why it's wrong here

    ECMP support does not block propagation.

  • DNS support is disabled on the transit gateway.

    Why it's wrong here

    DNS support does not affect route propagation.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The ANS-C01 exam often tests the distinction between transit gateway attachment and route propagation, trapping candidates who assume that simply attaching a VPC to a transit gateway automatically populates the route table with the VPC's CIDR.

Detailed technical explanation

How to think about this question

Transit gateway route tables require explicit propagation associations to automatically inject routes from attached resources (VPCs, VPNs, Direct Connect gateways). Without a TransitGatewayRouteTablePropagation resource in CloudFormation, the VPC's CIDR will not appear in the route table, even if the attachment is 'available'. This is a common misconfiguration because many assume attachment alone triggers propagation, but AWS separates attachment from route table association and propagation as distinct operations.

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

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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 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.

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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 transit gateway route table propagation is not configured. — Option B is correct because the exhibit shows a transit gateway route table attached to the VPC, but no propagation is configured. Without explicit propagation, the VPC attachment's CIDR blocks are not automatically added to the transit gateway route table. The CloudFormation resource AWS::EC2::TransitGatewayRouteTablePropagation must be declared to enable route propagation from the VPC attachment into the transit gateway route table.

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.

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Last reviewed: Jul 4, 2026

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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.