Assign a different DNS for a host in OpenWRT

There are occasions which I would like to set a host to use a different DNS server than the general DNS server set for the network.  I can do this easily with OPNSense however I can't seem to find the option in OpenWRT.  Initially it thought this isn't possible.  As it turns out, this is only not possible with Luci but it is doable if you are comfortable to tweak the configuration file directly.

To assign a host to use a specific DNS server, you need to edit the /etc/config/dhcp file.  For example, if I want to set my smart TV to use DNSForge.de instead of the Google DNS on my network, I need to assign a static address to my tv, and tag it with the "tag" option.  Then set the "dhcp_option" to the tagged host as below:

 

config host option dns '1' option ip '10.0.0.200' option name 'tv' option mac 'FF:1A:6B:1A:9A:9B' option tag 'tv_dns' option leasetime '300' config tag 'tv_dns' list dhcp_option '6,176.9.93.198,176.9.1.117'

ref: https://forum.openwrt.org/t/configure-host-specific-dns-server-over-dhcp-option-6/71471/4

ref: https://zedt.eu/tech/linux/how-to-serve-custom-dhcp-configuration-with-openwrt-dnsmasq/