Jason has set a firewall policy that allows only a specific list of network services...

The strategy described is known as a “default deny” firewall policy. This approach means that the firewall is configured to deny all traffic by default, except for the network services that are explicitly allowed. It is a restrictive security stance where only specified services are permitted, and everything else is blocked. This is considered a best practice in firewall configuration because it minimizes the attack surface by ensuring that only necessary services are accessible, thereby reducing the potential vectors for attack.

References: The concept of a default deny policy is a fundamental principle in network security and is advocated by various cybersecurity authorities, including the EC-Council’s Certified Network Defender (CND) program. It is also detailed in cybersecurity literature and aligns with best practices from organizations such as the National Institute of Standards and Technology (NIST)123.