Which of the following is a standard action taken by a firewall when a rule is matched?

The action taken by a firewall when a rule is matched can vary based on the configuration of the firewall and the specific rule that is triggered. When a firewall rule is matched, one of the standard actions that can be taken is to "deny" the traffic. This means that any packets or data that meet the conditions of this specific rule will be blocked from passing through the firewall, effectively preventing that traffic from reaching its intended destination.

Denying traffic is a fundamental function of firewalls as it serves to protect the network from unauthorized access or potentially harmful data. For instance, if a firewall rule is set to deny all incoming traffic from a particular IP address that has been identified as malicious, the firewall will reject any traffic from that source automatically.

While logging, alerting, and accepting are also actions that a firewall can perform, those typically serve different purposes. Logging records the traffic for later analysis, alerting would notify administrators of certain events, and accepting allows the specified traffic through the firewall. In this context, denying is specifically about preventing potentially harmful or unwanted traffic from entering the network, making it a critical action in maintaining network security.