Quick Answer
The answer is AWS WAF with an IP set rule. AWS WAF allows you to create IP sets—collections of IP addresses and CIDR ranges—that can be used in web ACL rules to explicitly allow or block traffic, making it the ideal service for restricting access to specific business partner IPs. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of the difference between stateless network-layer filtering (Security Groups and Network ACLs) and application-layer filtering with WAF. A common trap is choosing Security Groups, but they cannot manage dynamic, reusable IP lists across multiple resources, nor do they support allow-listing from disparate sources without complex CIDR management. Network ACLs are stateless and operate at the subnet level, lacking the granularity for partner-specific IP sets. Route 53 handles DNS routing, not traffic filtering. Memory tip: think of WAF IP sets as a “guest list” for your application—only invited IPs get past the door.
This ANS-C01 practice question tests your understanding of network design. 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 is deploying an internet-facing application in AWS. The application must only accept traffic from specific IP addresses of business partners. Which AWS service should be used to enforce this restriction?
Network ACLs with inbound allow rules
Why wrong: Network ACLs are stateless and less suitable for dynamic IP allow lists.
Security Groups with inbound allow rules
Why wrong: Security Groups cannot reference IP sets from external partners.
Amazon Route 53 geoproximity routing
Why wrong: Route 53 routing does not filter traffic to the application.
AWS WAF with an IP set rule
AWS WAF can filter traffic based on IP addresses using IP sets.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
AWS WAF with an IP set rule
Option A is correct because AWS WAF allows you to create IP set rules to block or allow traffic from specific IP addresses. Option B is wrong because Security Groups do not support allow lists for specific IP addresses from different sources (they support CIDR blocks but not dynamic IP sets). Option C is wrong because Network ACLs are stateless and operate at the subnet level; they can allow/deny by CIDR but are not as flexible as WAF for partner IP lists. Option D is wrong because Route 53 is for DNS, not traffic filtering.
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
For each option: why learners choose it and why it is or isn't the right answer here.
Network ACLs with inbound allow rules
Why it's wrong here
Network ACLs are stateless and less suitable for dynamic IP allow lists.
Security Groups with inbound allow rules
Why it's wrong here
Security Groups cannot reference IP sets from external partners.
Amazon Route 53 geoproximity routing
Why it's wrong here
Route 53 routing does not filter traffic to the application.
AWS WAF with an IP set rule
Why this is correct
AWS WAF can filter traffic based on IP addresses using IP sets.
Related concept
CIDR notation defines the prefix length.
Common exam traps
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
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.
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
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.
What to study next
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.
Network Design — study guide chapter
Learn the concepts, then practise the questions
Network Design 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
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise ANS-C01 questions linked to Network Management and Operations.
Practise ANS-C01 questions linked to Network Security, Compliance and Governance.
Practise ANS-C01 questions linked to Network Design.
Practise ANS-C01 questions linked to Network Implementation.
Practise ANS-C01 questions linked to ANS-C01 fundamentals.
Practise ANS-C01 questions linked to ANS-C01 scenario.
Practise ANS-C01 questions linked to ANS-C01 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Network Design — This question tests Network Design — CIDR notation defines the prefix length..
The correct answer is: AWS WAF with an IP set rule — Option A is correct because AWS WAF allows you to create IP set rules to block or allow traffic from specific IP addresses. Option B is wrong because Security Groups do not support allow lists for specific IP addresses from different sources (they support CIDR blocks but not dynamic IP sets). Option C is wrong because Network ACLs are stateless and operate at the subnet level; they can allow/deny by CIDR but are not as flexible as WAF for partner IP lists. Option D is wrong because Route 53 is for DNS, not traffic filtering.
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.
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 →
Last reviewed: Jun 20, 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.