An application filter is a dynamic object that groups applications based on their defined attributes, such as category, subcategory, technology, or risk factor. By creating a filter for the 'file-sharing' subcategory, the Security policy will automatically include any new applications that Palo Alto Networks classifies under this subcategory in future content updates. This approach ensures the policy remains current without requiring the administrator to manually update the policy or a static object group each time a new file-sharing application is identified, directly fulfilling the core requirement of the question.

A. A URL category matches traffic based on the website's URL, not the specific application (App-ID) being used for file sharing.

B. This is also a URL category. It is not a dynamic application-based object and would not automatically incorporate new file-sharing App-IDs.

C. An application group is a static list of specific applications. It would require manual updates to add new file-sharing App-IDs.

1. Palo Alto Networks. (2021). PAN-OS® Administrator’s Guide 10.2. "Objects > Application Objects > Create an Application Filter". The guide states

"An application filter dynamically groups applications based on application attributes... When a content update includes a new application that matches the attributes you defined for the filter

the new application is automatically added to the filter."

2. Palo Alto Networks. (2023). PCNSA Study Guide. "Chapter 4: Securing Traffic with Security Policies". This guide contrasts static application groups with dynamic application filters

explaining that filters are the appropriate tool when the goal is to create a policy that automatically adapts to new applications matching specific criteria

such as a subcategory.

3. Palo Alto Networks TechDocs. "Application Filter". This document explicitly details the dynamic nature of application filters: "Because an application filter is a dynamic object

you don’t have to update it when a content release includes new applications that match the filter criteria."