Enter custom DNS servers in your Asus Merlin firmware to avoid using your ISP DNS, which will steal and collect your browsing data.
Login to Asus Merlin firmware settings in a browser on any computer or smart device.
1. Under Advanced Settings select LAN.
2. Click the DHCP Server tab.
3. In the DNS Server 1 and DNS Server 2 fields enter the DNS server that you wish to use.

4. Click Apply and then reboot the router and reconnect to the network.