Traffic hitting policy rule it shouldn't

L1 Bithead

So I changed it to '' and it worked! thanks!


So if I was asked to block domains such as,, etc., I must put 'www' at the begining if it's not actually necessery for normal browsing?


Also, does using URL category in policy rules make the PaloAlto perform a reverse DNS lookup on each packet going through the system? and if so doesn't it have a big impact on performace?

L2 Linker

The URL is defined by website. In the case of an HTTP request to '', the website responds with a 301 (Permanently Moved) to ''. If you are using Chrome, it will hide the 'www.', but if you click on it will show it. If you use Firefox, you will see that you put in '' and then it is changed to ''. You can use Developer tools on either browser to see what the URL should be by following the request URL.


The firewall doesn't attempt to do a reverse DNS lookup on URL categories. The URL is determined by looking by looking at the HTTP headers, the SSL Client Hello SNI, and SSL Server Hello Common Name (CN) of the Server Certificate Subject DN. This behavior changes if SSL decryption is used.

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