A total count of blocked firewall connections describes an outcome generated by the control , rather than measuring how effectively the firewall itself performs against an established operational objective. It is therefore better characterized as a Key Result Indicator (KRI) in the terminology used by the course material.
For example, observing five million blocked connections does not demonstrate that a firewall is performing better than one that blocks one million. The total is heavily influenced by external conditions such as Internet scanning, bot activity, exposure of public services, and changing adversary traffic. The number can increase even when no improvement has occurred in firewall configuration, reliability, policy quality, or security effectiveness.
A meaningful KPI should connect directly to measurable performance—for example control availability, policy deployment accuracy, remediation time, rule-review compliance, or another defined operational objective. Firewall-block volume may remain useful as contextual or trend information, but treating it as a performance metric can produce misleading conclusions about security-program effectiveness.
The supplied study material contains this firewall KPI/KRI distinction.
Study Guide topics: security metrics, KPI versus KRI, control effectiveness, perimeter security, security-program reporting.
