How can a firewall administrator block a list of 300 unique URLs in the most...

For large lists of specific URLs, creating a custom URL category and importing the list is the most efficient approach for granular URL filtering.

“You can create custom URL categories to define specific URLs or patterns and enforce policies for these categories. This is the most efficient way to handle large sets of URLs.”

(Source: Custom URL Categories)

This approach saves time compared to manual rule creation or using generic application filters.