CAS-004 Security Engineering Practice Question
A company is migrating its legacy VPN to use IPsec with IKEv2. The security team wants to ensure the strongest possible security. Which THREE configuration options should be selected?
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 ECDSA P-384 for authentication
IKEv2, AES-256-GCM for encryption, and ECDSA for authentication provide strong security. AES-128 is weaker, SHA-1 is deprecated, and IKEv1 is legacy.
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 ECDSA P-384 for authentication
Why this is correct
ECDSA P-384 provides strong public key authentication.
- ✗
Use SHA-1 for integrity
Why it's wrong here
SHA-1 is deprecated; SHA-256 or higher should be used.
- ✓
Use AES-256-GCM for encryption
Why this is correct
AES-256-GCM provides strong encryption with authenticated data.
- ✗
Use IKEv1 instead of IKEv2
Why it's wrong here
IKEv2 is more secure and supports mobility.
- ✓
Enable perfect forward secrecy (DHE)
Why this is correct
PFS ensures session keys are not compromised if long-term keys are leaked.
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
Go deeper
Related to this question
About these practice questions
This CAS-005 question is part of Courseiva's 968-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 CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.