How should a firewall policy be structured?

A firewall policy should be structured from the most specific to the least specific rules. This approach is important because it allows the firewall to process policies in a way that prioritizes precise conditions before broader rules.

When a packet arrives at the firewall, it is evaluated against the rules in the order they are configured. If a rule is specific, it can match packets that fulfill particular criteria, providing tighter control over traffic. Specific rules may include certain IP addresses, ports, or protocols that are required for a particular application or service.

If a broad rule is placed at the top of the list, it could potentially allow or block traffic before more specific rules are evaluated, leading to unintended access or denial of service. Therefore, structuring the policy from most specific to least specific ensures that critical security needs are met first before applying general rules that might allow more traffic.

This structured approach is essential for effective firewall management and for ensuring that security policies are enforced correctly and efficiently.