When should you use the Reject action in a firewall policy?

The use of the Reject action in a firewall policy is primarily aimed at aiding in troubleshooting firewall configuration issues. When a Reject action is invoked, it explicitly denies the traffic while notifying the sending device that the connection has been rejected. This is particularly useful for identifying misconfigurations or issues with specific traffic flows, as it allows the administrator to understand that traffic is being blocked intentionally rather than being dropped silently.

This visibility can be critical during the troubleshooting process, as it provides feedback on the firewall's behavior and enables the administrator to make adjustments as necessary. By using the Reject action, you can confirm that the traffic is not passing due to policy settings, simplifying the diagnosis of problems in the network.