These steps will help to use an upstream DNS Server instead of your ISPs DNS Servers, and still benefit from the ad-blocking Diversion offers.
Note that for this to work, and Diversion in general, both fields DNS Server 1 and DNS Server 2 need to be empty in LAN/DHCP Server.
Many public DNS Servers are available, Google offers theirs with 8.8.8.8 and 8.8.4.4, other providers are OpenDNS and OpenNIC. Wikipedia has a short list of trusted DNS Servers.
To use upstream DNS Server(s), navigate to WAN/Internet connection on your Asus router.
Set Connect to DNS Server automatically to No.
As in the picture above, set DNS Server(s) to your preferred DNS resolver.
Click on Apply and you're all set.
Upstream DNS queries are now answered by these DNS Server(s), while queries for local resources are answered directly by Dnsmasq, the built in DNS resolver on your router. Dnsmasq also answers all queries for blocked domains in Diversion.
Last update on 2018-10-10 by thelonelycoder.