URL filtering is a feature in Palo Alto Networks firewalls that allows administrators to block access to specific URLs [1]. This feature can be configured via four different objects: Custom URL categories in URL Filtering profiles, PAN-DB URL categories in URL Filtering profiles, External Dynamic Lists (EDL) in URL Filtering profiles, and Custom URL categories in Security policy rules. The evaluation order for URL filtering is: Custom URL categories in URL Filtering profile, PAN-DB URL categories in URL Filtering profile, EDL in URL Filtering profile, and Custom URL category in Security policy rule. This information can be found in the Palo Alto Networks PCNSE Study Guide, which can be accessed here: https://www.paloaltonetworks.com/documentation/80/pan-os/pan-os/resource-library/palo-alto-networks-pcnse-study-guide.html.