What is the purpose of security zones in a firewall?

The purpose of security zones in a firewall is to segment network traffic and enforce policies. Security zones create distinct areas within the network where specific security policies can be applied to control the flow of traffic between them. By categorizing network interfaces into different zones— such as untrusted, trusted, and DMZ (demilitarized zone) —firewalls can apply rules that dictate what data can pass between these zones. This segmentation enhances security by allowing for tailored configurations based on the sensitivity of the data and the level of access required for different users or systems.

For instance, traffic coming from an untrusted zone such as the internet can be subjected to stringent inspection and limitations before being allowed into a wholly trusted zone that houses critical internal servers. This focused approach prevents unauthorized access and mitigates risks by ensuring that only the necessary ports and protocols are enabled, thus enforcing proper policies across different areas of the network.

In contrast, the other options do not accurately reflect the primary role of security zones. While increasing network speed, reducing costs, or providing user authentication may be beneficial to network performance and management, they are not the core purposes of employing security zones in a firewall context.