ANS-C01 Network Management and Operations Practice Question
A company uses AWS Site-to-Site VPN to connect its on-premises network to AWS. The VPN connection is established, but traffic from on-premises to AWS is not working. The on-premises network team confirms that the on-premises firewall is allowing traffic to the VPC CIDR. What should the network engineer check in AWS to resolve the issue?
⚠ Common exam trap
Watch out — candidates often assume a tunnel status of UP (Option A) guarantees traffic flow, but AWS explicitly separates tunnel health from routing configuration, and the exam tests this distinction by requiring you to check the VPC route tables for the correct target.
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
✓
Check the VPC route tables to ensure routes to the on-premises network point to the virtual private gateway.
Even if the VPN tunnel is up and BGP is peering, traffic will not flow unless the VPC route tables have a route pointing to the virtual private gateway (VGW) for the on-premises CIDR. Without this route, the VPC has no path to forward return traffic back to the on-premises network, causing asymmetric routing or blackholing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Verify that the VPN tunnel status is UP.
Why it's wrong here
The VPN is established, so tunnels are likely up.
- ✗
Review the customer gateway configuration for incorrect BGP settings.
Why it's wrong here
The customer gateway is on-premises; the question asks what to check in AWS.
- ✗
Ensure the virtual private gateway is attached to the correct VPC.
Why it's wrong here
If the VPN is established, the virtual private gateway is attached.
- ✓
Check the VPC route tables to ensure routes to the on-premises network point to the virtual private gateway.
Why this is correct
Missing routes in the VPC route table would prevent inbound traffic from reaching instances.
Visual reference
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
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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.