← ANS-C01·Amazon Web Services

Question 981 of 1,705

Network Management and Operations →mediumMultiple ChoiceObjective-mapped

ANS-C01 Network Management and Operations Practice Question

This ANS-C01 practice question tests your understanding of network management and operations. 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.

A company uses a VPC with multiple subnets in different Availability Zones. The VPC has a NAT Gateway in a public subnet of us-east-1a, and a second NAT Gateway in us-east-1b for high availability. Each private subnet in us-east-1a routes 0.0.0.0/0 to the NAT Gateway in us-east-1a, and private subnets in us-east-1b route to the NAT Gateway in us-east-1b. The company's EC2 instances in private subnets need to access an external service using IPv6. The VPC is not configured for IPv6. The network engineer needs to enable IPv6 connectivity for these instances. Which solution is the most cost-effective and scalable?

A
Add an IPv6 CIDR block to the VPC and configure a NAT64 gateway to translate IPv6 to IPv4.
Why wrong: NAT64 is for IPv6-only clients accessing IPv4 services, not the other way.
B
Add an IPv6 CIDR block to the VPC, assign IPv6 addresses to private subnets, and add a route for ::/0 to an egress-only internet gateway.
Egress-only IGW allows outbound IPv6 traffic from private subnets.
C
Attach an internet gateway to the VPC and add a route for ::/0 to the internet gateway in the private subnets.
Why wrong: Internet gateway requires instances to have public IPv6 addresses, which is not typical for private subnets.
D
Add an IPv6 CIDR block to the VPC and use the existing NAT Gateways with IPv6.
Why wrong: NAT Gateways do not support IPv6.

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

✓

Add an IPv6 CIDR block to the VPC, assign IPv6 addresses to private subnets, and add a route for ::/0 to an egress-only internet gateway.

Option B is correct. Since the VPC is not IPv6-enabled, adding an IPv6 CIDR block assigns IPv6 addresses to subnets. For outbound-only IPv6 access from private subnets, an egress-only internet gateway (EIGW) is the appropriate and most cost-effective solution because it allows outbound traffic to the internet while preventing inbound connections, similar to a NAT gateway for IPv4. A route for ::/0 to the EIGW from the private subnets achieves the goal. Option A is incorrect because NAT64 translates IPv6 to IPv4, but the target service uses IPv6, so no translation is needed. Option C is incorrect because an internet gateway would permit inbound traffic and instances would need public IPv6 addresses, which is not stated and is less secure. Option D is incorrect because NAT Gateways do not support IPv6.

Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Add an IPv6 CIDR block to the VPC and configure a NAT64 gateway to translate IPv6 to IPv4.
Why it's wrong here
NAT64 is for IPv6-only clients accessing IPv4 services, not the other way.
✓
Add an IPv6 CIDR block to the VPC, assign IPv6 addresses to private subnets, and add a route for ::/0 to an egress-only internet gateway.
Why this is correct
Egress-only IGW allows outbound IPv6 traffic from private subnets.
Related concept
CIDR notation defines the prefix length.
✗
Attach an internet gateway to the VPC and add a route for ::/0 to the internet gateway in the private subnets.
Why it's wrong here
Internet gateway requires instances to have public IPv6 addresses, which is not typical for private subnets.
✗
Add an IPv6 CIDR block to the VPC and use the existing NAT Gateways with IPv6.
Why it's wrong here
NAT Gateways do not support IPv6.

Common exam traps

Common exam trap: usable hosts are not the same as total addresses

Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.

Detailed technical explanation

How to think about this question

Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.

KKey Concepts to Remember

CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.

TExam Day Tips

Write the block size before choosing the subnet.
Check whether the question asks for hosts, subnets or a specific address range.
Do not confuse /24, /25, /26 and /27 host counts.

Key takeaway

Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.

Real-world example

How this comes up in practice

A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

Visual reference

What to study next

Got this wrong? Here's your next step.

Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.

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 Management and Operations — This question tests Network Management and Operations — CIDR notation defines the prefix length..

What is the correct answer to this question?

The correct answer is: Add an IPv6 CIDR block to the VPC, assign IPv6 addresses to private subnets, and add a route for ::/0 to an egress-only internet gateway. — Option B is correct. Since the VPC is not IPv6-enabled, adding an IPv6 CIDR block assigns IPv6 addresses to subnets. For outbound-only IPv6 access from private subnets, an egress-only internet gateway (EIGW) is the appropriate and most cost-effective solution because it allows outbound traffic to the internet while preventing inbound connections, similar to a NAT gateway for IPv4. A route for ::/0 to the EIGW from the private subnets achieves the goal. Option A is incorrect because NAT64 translates IPv6 to IPv4, but the target service uses IPv6, so no translation is needed. Option C is incorrect because an internet gateway would permit inbound traffic and instances would need public IPv6 addresses, which is not stated and is less secure. Option D is incorrect because NAT Gateways do not support IPv6.

What should I do if I get this ANS-C01 question wrong?

What is the key concept behind this question?

CIDR notation defines the prefix length.

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.