Multiple custom DNS servers question

Installing and Using OpenWrt
1

So, I have two pi-holes on the lan for handling DNS. What I see in Luci (interfaces -> lan -> dhcp -> advanced) lists both of them:

6, 192.168.1.82
6, 192.168.1.209

Does that mean 82 will be used first, and 209 will be used when 82 can't be found? That is what I want to happen.

The broader context is that I have pihole running in docker on openmediavault (OMV). The docker network it's connected to is a "macvlan" so other machines on the network can refer to it on 192.168.1.82 instead of the host (OMV) ip address at 192.168.1.214.

This works great for everything else on the network, but OMV itself does not appear to be able to see 192.168.1.82. There's some documentation (at the bottom) on modifying OMV so the containers and host can see each other, but I want to better understand what it's doing before just copying and pasting it because there are some dire warnings.

In the meanwhile, it's easy to just create a 2nd pihole that OMV should be able to see without dealing with hosts/containers. But dns requests only get routed to the 2nd entry if I remove the first one.

Is there a different / better way to have one device on the network use a specific DNS?

2

Wrong, Option 6 is a list, so it should be one record with two servers.

It depends entirely on the client.

3

We can only stretch this more then once.

4

For such a scenario, an better solution would be the standard setup, to have openwrt-box configured as DNS server, to do “DNS hijacking” (to force all clients to use openwrt as DNS provider), and then to configure dnsmasq to have the two piholes as upstream resolvers. For a strict backup-conf, dnsmasq needs the special option “strict-order”. WIthout it, both piholes would be queried simultaneously. Consult https://openwrt.org/docs/guide-user/firewall/fw3_configurations/intercept_dns