What happens when at least one outgoing Allow rule is assigned in a firewall?

When at least one outgoing Allow rule is assigned in a firewall, the mechanism by which network traffic is controlled shifts toward a restrictive mode. In this context, restrictive mode essentially implies that the firewall will primarily block all traffic unless explicitly allowed by an outgoing rule. This ensures that only specified types of communication can pass through, providing an additional layer of security.

This approach mitigates the risk of unauthorized access and data leaks, as it requires specific permissions for outbound connections. It's essential to understand that in a restrictive model, the default behavior is to deny all traffic unless it meets the criteria defined by the Allow rules.

Conversely, if a firewall operates in permissive mode, it would allow all outbound traffic, which would defeat the purpose of using the firewall to enforce security policies. Therefore, having an Allow rule does not mean the firewall opens up completely but rather, it establishes controlled and secure pathways for traffic, highlighting the importance of a deeply considered firewall configuration.