The answer is to use an S3 bucket policy with a condition that limits access to specific IP addresses, and this can also be combined with an IAM policy. This works because S3 bucket policies support the `aws:SourceIp` condition key, which evaluates the requester’s IP address at the time of the request, allowing you to explicitly deny or allow access from a defined range. On the AWS Certified Security Specialty SCS-C02 exam, this question tests your understanding of where network controls can be applied to S3—a common trap is confusing security groups or network ACLs with S3, but S3 is a global service and cannot have those attached. Remember that VPC flow logs only monitor traffic, not restrict it. A quick memory tip: think of `aws:SourceIp` as the “bouncer at the door” for your bucket policy—it checks the IP before letting anyone in.
SCS-C02 Infrastructure Security Practice Question
This SCS-C02 practice question tests your understanding of infrastructure security. 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 wants to allow only specific IP addresses to access an S3 bucket. Which two methods can achieve this? (Choose TWO.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use an IAM policy with a condition that limits access to specific IP addresses.
Options A and B are correct. S3 bucket policies support the aws:SourceIp condition to restrict access based on IP addresses. Bucket policies can also be combined with IAM policies. Option C is wrong because security groups cannot be attached to S3. Option D is wrong because network ACLs cannot be attached to S3. Option E is wrong because VPC flow logs only monitor traffic.
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.
✓
Use an IAM policy with a condition that limits access to specific IP addresses.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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 SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
Infrastructure Security — This question tests Infrastructure Security — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Use an IAM policy with a condition that limits access to specific IP addresses. — Options A and B are correct. S3 bucket policies support the aws:SourceIp condition to restrict access based on IP addresses. Bucket policies can also be combined with IAM policies. Option C is wrong because security groups cannot be attached to S3. Option D is wrong because network ACLs cannot be attached to S3. Option E is wrong because VPC flow logs only monitor traffic.
What should I do if I get this SCS-C02 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related SCS-C02 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
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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. Which TWO actions are valid ways to restrict access to an Amazon S3 bucket using a bucket policy? (Choose two.)
medium
✓ A.Use the aws:SourceIp condition key to allow access only from a specific IP range.
B.Use the iam:RoleName condition key to allow access only from a specific IAM role.
✓ C.Use the aws:Referer condition key to allow access only from a specific HTTP referer.
D.Use the aws:SourceVpce condition key to allow access only from a specific VPC.
E.Use the kms:EncryptionContext condition key to require that objects are encrypted with a specific KMS key.
Why A: The correct answers are A and C. Option A is correct because you can use the aws:SourceIp condition key to restrict by IP address. Option C is correct because you can use the aws:Referer condition key to restrict by HTTP referer. Option B is wrong because aws:SourceVpce is for VPC endpoints, but it is used in bucket policies to restrict access to a specific VPC endpoint, not a VPC ID. Option D is wrong because IAM roles are not used directly in bucket policies; you use the IAM role's ARN with the aws:PrincipalArn condition, but not with kms:EncryptionContext. Option E is wrong because kms:EncryptionContext is used in KMS key policies, not S3 bucket policies.
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This SCS-C02 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 SCS-C02 exam.
Question Discussion
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