ANS-C01 Network Implementation Practice Question
A company is using AWS Direct Connect with a public virtual interface to access Amazon S3. The on-premises network has a firewall that only allows traffic to specific IP prefixes. What is the best practice to ensure connectivity while maintaining security?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that a private VIF or VPN is required for secure access to AWS services, when in fact a public VIF with service-specific prefix lists provides a secure and simpler solution for accessing public services like S3.
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
✓
Use the S3 IP prefix list from AWS to create firewall rules.
AWS publishes managed prefix lists for each service, including Amazon S3, which contain the specific IP prefixes used by S3 in each region. By using these prefix lists in firewall rules, you can allow only the necessary S3 traffic while maintaining strict security, rather than permitting the entire region's IP range. This approach aligns with the principle of least privilege and ensures connectivity over the public VIF without exposing on-premises networks to unnecessary traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Allow all traffic to the AWS region's IP range.
Why it's wrong here
Allowing all region IPs is too permissive.
- ✗
Set up a Site-to-Site VPN tunnel over Direct Connect.
Why it's wrong here
VPN over Direct Connect is not needed for S3 access.
- ✗
Use a private virtual interface and connect through a VPC endpoint.
Why it's wrong here
Private VIF is for VPC, not direct S3 access.
- ✓
Use the S3 IP prefix list from AWS to create firewall rules.
Why this is correct
Prefix lists provide specific S3 IP addresses.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.