What happens during a Failure to apply rules?

When there is a failure to apply rules in a firewall, the expected behavior is that the firewall will block traffic. This is because firewalls are designed with a default stance that prioritizes security. If the rules that determine whether a certain type of traffic should be allowed or denied are not applied correctly or fail to execute, the firewall errs on the side of caution and blocks any potentially harmful or unauthorized traffic. This behavior is critical for maintaining network security as it prevents inadvertent exposure to vulnerabilities.

In contrast, options suggesting that the firewall will ignore all packets or allow all traffic imply a more permissive approach that is not typically standard in security settings. Additionally, while generating an alert may occur in some instances of rule failures, it is secondary to the primary action taken regarding traffic handling. Therefore, the correct answer emphasizes the default blocking action that aligns with security best practices when there is a failure in rule application.