CISSP Practice Question: An organization wants to ensure secure communications between its branch offices over…

Correct Answer: A. IPsec

Explanation (CISSP Manager Logic):

IPsec is the industry standard for site-to-site VPNs because it provides robust encryption, authentication, and integrity at the Network Layer. It offers the best balance of high-grade security and universal vendor interoperability required for connecting diverse branch office infrastructures.

By implementing IPsec, you:

• Ensure data confidentiality and integrity across untrusted public networks.
• Maintain high compatibility across various hardware vendors and operating systems.
• Support scalable, permanent tunnels suitable for enterprise-wide connectivity.

While the other options are relevant, they fall short because:

• B: PPTP is obsolete and contains significant security vulnerabilities that make it unsuitable for modern business use.
• C: SSTP is a proprietary Microsoft protocol, which limits its compatibility in heterogeneous device environments.
• D: L2TP lacks native encryption and must be paired with IPsec anyway, adding unnecessary overhead for this use case.

Think like a manager:

Prioritize standardized, vendor-neutral protocols that provide the strongest security posture while ensuring long-term scalability and interoperability for the entire organization.