CISSP Communication and Network Security Practice Question
An organization is deploying a VPN solution for remote employees. The security team requires a modern protocol with perfect forward secrecy, uses elliptic curve cryptography, and is known for its efficient, minimal codebase. Which VPN protocol should they choose?
⚠ Common exam trap
In the CISSP exam, candidates may incorrectly choose IPsec with IKEv2 because it supports PFS and ECC, but fail to recognize that only WireGuard is designed with a minimal, auditable codebase, which is explicitly required in the question.
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
✓
WireGuard
WireGuard is the correct choice because it is a modern VPN protocol that uses elliptic curve cryptography (Curve25519) for key exchange, provides perfect forward secrecy by default through its ephemeral session keys, and is designed with a minimal, auditable codebase (around 4,000 lines) for efficiency and security. These features directly match the organization's requirements for a modern protocol with PFS, ECC, and a lean implementation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
WireGuard
Why this is correct
WireGuard is a modern, high-performance VPN protocol distinguished by its extremely small codebase, which significantly reduces the attack surface and simplifies auditing. It leverages state-of-the-art cryptographic primitives, including ChaCha20 for symmetric encryption, Poly1305 for authentication, and Curve25519 for Elliptic Curve Cryptography (ECC) and Perfect Forward Secrecy (PFS) key exchange. This combination ensures robust security, exceptional speed, and efficient resource utilization, making it ideal for remote employees seeking a fast and secure connection.
- ✗
L2TP/IPsec
Why it's wrong here
L2TP/IPsec, while capable of providing perfect forward secrecy and utilising elliptic curve cryptography via IKEv2, does not represent the most modern protocol known for an efficient, minimal codebase. L2TP is an older tunnelling protocol, which, when combined with IPsec, typically results in a heavier implementation compared to newer alternatives. This option is tempting because IPsec is a robust, widely adopted security framework offering strong encryption and authentication, making it a common choice for enterprise remote access and site-to-site VPNs where broad interoperability is prioritised.
- ✗
PPTP
Why it's wrong here
Point-to-Point Tunneling Protocol (PPTP) is an outdated VPN protocol that relies on weak authentication mechanisms like MS-CHAPv2, which is highly vulnerable to offline dictionary and brute-force attacks. It completely lacks Perfect Forward Secrecy (PFS), meaning that if a long-term key is ever compromised, all past session traffic encrypted with that key can be decrypted. Its inherent security flaws and legacy status make it unsuitable for any modern secure communication requirement.
- ✗
IPsec with IKEv2
Why it's wrong here
While IPsec with IKEv2 is a robust and widely adopted VPN framework capable of providing strong security and Perfect Forward Secrecy (PFS) when properly configured, it is not inherently designed around Elliptic Curve Cryptography (ECC) as its primary cryptographic primitive. Its larger and more complex codebase, compared to WireGuard, can introduce a greater attack surface and often requires more intricate configuration for optimal security and performance. Although powerful, its general-purpose nature means it isn't as streamlined or efficient for simple remote access VPNs as newer, purpose-built protocols.
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
Learn chapter
Security Governance and Principles
Key term
VPN
A VPN (Virtual Private Network) creates a secure, encrypted tunnel between your device and a remote server, protecting your data and hiding your online activity.
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
About these practice questions
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISSP practice question is part of Courseiva's free ISC2 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 CISSP exam.