ANS-C01 Network Implementation Practice Question
A company uses AWS Direct Connect with a public VIF to access Amazon S3. They notice that traffic to S3 is taking a suboptimal path (going through the internet) instead of the Direct Connect connection. The VPC has a route table with a route for S3 prefix list via the virtual private gateway. What is the most likely cause?
⚠ Common exam trap
Many candidates assume the VPC route table configuration is sufficient, but they overlook that the on-premises router must also advertise the destination prefixes via BGP over the public VIF for traffic to use the Direct Connect path.
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 on-premises router is not advertising the S3 prefix list via BGP over the public VIF
For traffic to use the Direct Connect public VIF, the on-premises router must advertise the specific prefixes (e.g., S3 prefix list) via BGP over the public VIF. Without this advertisement, the on-premises router will not have a route pointing to the Direct Connect link for S3 traffic, causing it to fall back to the internet path. The VPC route table already has a route for the S3 prefix list via the virtual private gateway, so the issue lies in the BGP advertisement from the on-premises side.
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 does not have a VPC endpoint for S3
Why it's wrong here
VPC endpoint is optional; public VIF can access S3 directly.
- ✗
The public VIF is not associated with the correct Direct Connect gateway
Why it's wrong here
Association is likely correct if other routes work.
- ✓
The on-premises router is not advertising the S3 prefix list via BGP over the public VIF
Why this is correct
S3 prefix must be advertised to route traffic over Direct Connect.
- ✗
The route table in the VPC does not have a route to the S3 prefix list via the virtual private gateway
Why it's wrong here
Route exists as stated.
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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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.