Which statement best captures the requirement to restrict inbound and outbound traffic for the CDE?

Which statement best captures the requirement to restrict inbound and outbound traffic for the CDE?

• A. Restrict inbound and outbound traffic to what is necessary for the CDE, and deny all other traffic.
• B. Allow all inbound traffic from the Internet if outbound traffic is restricted.
• C. Only monitor traffic; no restrictions are required.
• D. Outbound traffic must always be allowed.

Answer: (A)

The central concept is enforcing a default-deny firewall posture that restricts inbound and outbound traffic to only what is necessary for the CDE. By allowing only the specific, required connections and blocking everything else, you minimize the exposure of cardholder data and strengthen segmentation. This least-privilege approach is a fundamental control for protecting the CDE and is a direct reflection of PCI DSS network security expectations. Why this is the best fit: restricting to the minimum necessary means that only the essential services, ports, and protocols that support business needs are allowed, and all other traffic is denied by default. This reduces the risk of unauthorized access or data leakage. The other options fail because they either permit unnecessary inbound access from the Internet, rely only on monitoring without implementing actual controls, or allow all outbound traffic, which undermines the goal of restricting exposure and maintaining tight control over communications.

The central concept is enforcing a default-deny firewall posture that restricts inbound and outbound traffic to only what is necessary for the CDE. By allowing only the specific, required connections and blocking everything else, you minimize the exposure of cardholder data and strengthen segmentation. This least-privilege approach is a fundamental control for protecting the CDE and is a direct reflection of PCI DSS network security expectations.

Why this is the best fit: restricting to the minimum necessary means that only the essential services, ports, and protocols that support business needs are allowed, and all other traffic is denied by default. This reduces the risk of unauthorized access or data leakage. The other options fail because they either permit unnecessary inbound access from the Internet, rely only on monitoring without implementing actual controls, or allow all outbound traffic, which undermines the goal of restricting exposure and maintaining tight control over communications.