Just wanted to post on this subject since I appears that PAN has updated the behavior of precedence in URL Filtering Profiles.
On systems running 8.X code, it does appear that the order of precendence follows what is outlined in https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClsmCAC, however, I am running 9.0.6 on my PA-220, and URL Filtering appears to have an additional factor in assigning priority...the source of the list (custom, EDL, pre-defined).
I ran a test of this in my lab. In this example, I'm browsing to "jack.com". You can see the URL is ultimately categorized as "streaming-media", however there is a list that shows all lists that this URL is a member of...interesting to note, it shows my EDL "URL", but I have this set to "none" in the filter profile, so I would have expected it to not show up, just the same as my custom URL categories, but it's there.
I have a custom URL category and EDL that both have entry "jack.com"
In my URL filtering profile, I have my custom URL category set to "none".
I have my EDL set to "none".
Per the logs, I know the pre-defined categories of "streaming-media" and "low-risk" were listed, so those are set to "alert".
First, to test the effect of "block" versus "alert" in the same category group, I change "low-risk" to block to see if it will take precedence over "streaming-media".
It does, as the category is now "low-risk" and the action is "block-url".
So, with "low-risk" still set to block, I update my EDL entry to "alert" and test traffic again.
Sure enough, the EDL alert took priority over the pre-defined category block.
Of course, if I set the EDL to "block", it's still the matching category and does block as expected.
Now, with the pre-defined and EDL categories blocking, I update my custom URL category to "alert".
The traffic is reclassified as the custom category, and the traffic is allowed.
In the end, my URL filter profile looks like this.
Based on this behavior, it does appear that Palo provides a legend of matching priority based on how the groups are listed in the filtering profile (top down: custom, EDL, pre-defined).
I just wanted to point this out since it does appear that with 8.X code, regardless of the category group, a URL matching any "block" category cannot be overriden, regardless of the category group, but with 9.X, it is now possible. Personally, I like this feature. If PAN categorizes a web site to a specific category that I happen to be blocking in a URL filtering profile, I can use a custom category "white list" to allow it, avoiding any need to make a new policy with matching criteria and a different content inspection profile.
