What is a firewall rule?

What is a firewall rule?

• A. An instruction that allows or blocks network traffic based on criteria.
• B. A policy to enforce passwords.
• C. A device that monitors bandwidth usage.
• D. A method of data backup.

Answer: (A)

Firewall rules are instructions that tell the firewall whether to let or block specific network traffic by evaluating criteria such as where the traffic is coming from, where it’s going, the protocol, and the port, and then applying an action like allow or deny. This exact mechanism is what defines a firewall rule, so the option describing instructions to allow or block traffic based on criteria is the best match. Other options describe different IT functions—not how traffic is controlled by a firewall: password policies govern authentication, bandwidth monitors track usage, and data backups protect data. In practice, a rule might permit web traffic to a server on port 80 while blocking other ports from untrusted sources, illustrating how rules enforce access.

Firewall rules are instructions that tell the firewall whether to let or block specific network traffic by evaluating criteria such as where the traffic is coming from, where it’s going, the protocol, and the port, and then applying an action like allow or deny. This exact mechanism is what defines a firewall rule, so the option describing instructions to allow or block traffic based on criteria is the best match. Other options describe different IT functions—not how traffic is controlled by a firewall: password policies govern authentication, bandwidth monitors track usage, and data backups protect data. In practice, a rule might permit web traffic to a server on port 80 while blocking other ports from untrusted sources, illustrating how rules enforce access.