What does a firewall rule set define?

A firewall rule set defines the criteria for allowing or denying network traffic through the firewall. This is essential for maintaining security within a network by specifying which types of traffic are permitted to enter or exit. The rules can be based on various factors including source and destination IP addresses, ports, and protocols. A properly configured firewall rule set helps protect the network from unauthorized access and potential attacks by filtering out unwanted traffic.

In contrast, the other options touch on different aspects of network management. Data storage capacity refers to the amount of data that can be stored in systems and is not related to traffic control. Bandwidth usage limits pertain to the maximum amount of data that can be transferred over a network at any given time, which is distinct from firewall operations. User access permissions involve the authorization levels granted to users within systems, focusing on internal access rather than traffic filtering. Thus, the definition of a firewall rule set explicitly aligns with regulating network traffic based on specified criteria.