I have set up a DNS forwarding server on Ubuntu 20.04 LTS using Bind 9. I need to implement DNS whitelisting, however, I have not found any tutorials which explain how to set it up. I have tried looking at information about Response Policy Zones (RPZs) but they seem to be used only for blacklisting. I have also tried looking at "DNS and BIND 5th ed." but have not found any chapter describing whitelisting.
Please can somebody give me a link to a tutorial explaining me how to implement whitelisting or explain me below how it could be set up (and/or post a link containing a repo with the files/settings to put in my DNS server)? Thank you in advance.
P.S. Even though, I'd preffer to how how to implement this on BIND, I'm open to other DNS software implementations if there are well documented tutorials about how to set up a DNS forwarder and whitelisting.