Where should firewalls ideally be placed in a secure network?

The ideal placement of firewalls in a secure network is critically important to protect sensitive information, particularly when it comes to cardholder data environments. By positioning firewalls between the cardholder data environment and the internet, organizations create a robust layer of defense against external threats.

This configuration serves to monitor and control incoming and outgoing network traffic based on predetermined security rules, effectively acting as a barrier that helps prevent unauthorized access to sensitive data. The firewall mitigates risks associated with vulnerabilities that could be exploited by attackers originating from the internet, which is essential for maintaining the integrity and confidentiality of cardholder data.

Additionally, this approach supports compliance with security standards such as the Payment Card Industry Data Security Standard (PCI DSS), which emphasizes the necessity of protecting cardholder data through strong firewalls and segmentation from untrusted networks. By restricting direct access to the cardholder data environment, organizations can significantly reduce the surface area for potential attacks.

In contrast, other placements such as between user devices and local servers or within the cardholder data environment, while potentially useful in some scenarios, do not serve the primary purpose of safeguarding the sensitive cardholder data from external threats as effectively as placing the firewall at the perimeter.