ANS-C01 Network Implementation Practice Question
A company has a VPC with CIDR 10.0.0.0/16 and needs to connect to another VPC (192.168.0.0/16) using VPC peering. Both VPCs have overlapping CIDRs with some on-premises networks. What must be done to ensure proper routing?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that VPC peering can handle overlapping CIDRs by simply adding routes, but the trap is that AWS route tables require unique destination CIDRs for each next-hop, and overlapping ranges cause routing conflicts that break connectivity.
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
✓
Verify that the CIDR blocks do not overlap. If they do, you must re-IP one VPC or use other solutions like Transit Gateway with network address translation.
VPC peering requires non-overlapping CIDR blocks because AWS uses the destination CIDR to route traffic; if the CIDRs overlap, the route tables cannot distinguish between the two VPCs, causing asymmetric routing or dropped traffic. Option B correctly identifies that overlapping CIDRs must be resolved, either by re-IPing one VPC or using Transit Gateway with NAT capabilities to translate addresses and avoid conflicts.
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 AWS Transit Gateway instead and attach both VPCs.
Why it's wrong here
Transit Gateway also does not support overlapping CIDRs for direct routing; you would need additional configurations.
- ✓
Verify that the CIDR blocks do not overlap. If they do, you must re-IP one VPC or use other solutions like Transit Gateway with network address translation.
Why this is correct
Without overlap, peering works. Overlap requires re-IP or alternative solutions.
- ✗
Use a NAT gateway in one VPC to translate addresses.
Why it's wrong here
NAT is for outbound traffic, not for solving overlapping CIDRs in peering.
- ✗
Create the peering connection and add routes for the full CIDR ranges in both route tables.
Why it's wrong here
Overlapping CIDRs cause routing conflicts; peering may not work.
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.