ANS-C01 Network Design Practice Question
A company is designing a network for a new VPC. They want to ensure that the VPC can connect to an on-premises data center via a site-to-site VPN. The on-premises network uses a CIDR block of 10.0.0.0/8. The VPC will use a CIDR block of 10.0.0.0/16. The network engineer is concerned about overlapping IP addresses. What is the best way to avoid IP address overlap?
⚠ Common exam trap
AWS often tests the misconception that NAT can always solve IP overlap issues, but the best practice is to design non-overlapping private IP spaces from the start to avoid complexity and routing failures.
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 a different RFC 1918 CIDR block for the VPC
Using a different RFC 1918 CIDR block (e.g., 172.16.0.0/12 or 192.168.0.0/16) for the VPC completely avoids IP address overlap with the on-premises 10.0.0.0/8 network. Overlapping CIDR blocks (both using 10.0.0.0/8) would prevent successful route propagation and cause asymmetric routing or connectivity failures in the site-to-site VPN. NAT can mitigate overlap but adds complexity and is not the 'best' design choice when a non-overlapping private range is available.
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 the same CIDR block and rely on NAT
Why it's wrong here
Overlap will cause routing issues.
- ✓
Use a different RFC 1918 CIDR block for the VPC
Why this is correct
Avoids overlap.
- ✗
Use a smaller subnet within the same 10.0.0.0/8 range
Why it's wrong here
Still overlaps.
- ✗
Use a public IP range for the VPC
Why it's wrong here
Public IPs are not recommended for private VPCs.
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 |
Go deeper
Related to this question
About these practice questions
This ANS-C01 question is part of Courseiva's 1,621-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.