Firewall registers WildFire even though WildFire is not configured in the firewall

Why does the firewall automatically register the WildFire public cloud when passive DNS monitoring is enabled in the anti-spyware profile?

Passive DNS is an opt-in feature that enables the firewall to act as a passive DNS sensor and send selected DNS information to Palo Alto Networks for analysis in order to improve threat intelligence and threat prevention capabilities.

This document can help you learn more about Passive DNS monitoring.

The firewall uses the WildFire public cloud to send selected DNS information to Palo Alto Networks, and when we enable Passive DNS monitoring, the firewall automatically registers the WildFire public cloud even though WildFire has not been configured on the firewall.