PAN-OS is the software that runs all Palo Alto Networks
next-generation firewalls. Palo Alto Networks also frequently publishes
updates to equip the firewall with the latest security features.
The firewall can enforce policy based on the applications and threat
signatures (and more) that content updates provide, without requiring
you to update the firewall configuration.
After you successfully download and install a PAN-OS software
update on your physical firewall, the software update is validated
after the physical firewall reboots as part of the software installation
process to ensure the PAN-OS software integrity. This ensures that
the new running software update is known good and that the firewall
is not compromised due to remote or physical exploitation.