Currently in the Network Zones → Blocked Zones settings. While bugged and not working, adding Host Name does not exactly block that DNS. Because many ads servers DNS have many different host names and IPs that will return and they cycle them constantly.
I know it will slow down internet, but I would like an option to add a request to block an Host name (with wildcards) by sending a request for any internet traffic for a reverse DNS lookup based on the current IP address. Or just by doing a ping, which displays the host name.