Multiple dnsmasq instances + DHCP options

Installing and Using OpenWrt
1

I'm apparently trying to do something... uncommon? Running 24.10.2 in production, testing on 25.12.1. I've long had just the one/default dnsmasq instance running, using lan as the local domain.

I have a fqdn, and I want to apply subdomains to a few of my vlan subnets a la home.fqdn.com, iot.fqfn.com, etc.

I can easily change the main lan domain; clients show on the status page as client.home.fqdn.com, can be pinged at that, and so on.

But when I create another instance in DHCP or DNS (in 25.12.1), the interface that it's associated with then shows no DHCP server setup. Running through Set up DHCP server on the interface again, the related dnsmasq instance/settings disappear after luci commits:

uci set dhcp.iot=dhcp
uci set dhcp.iot.interface='iot'
uci del dhcp.iot.domain

If I go in and manually edit /etc/config/dhcp, adding option domain 'iot.fqdn.com' to the section, and /etc/init.d/dnsmasq restart, it'll stay. But once I change something in luci, say the lease time, it again wants to delete the domain:

uci del dhcp.iot.domain
uci set dhcp.iot.leasetime='2h'

Seems these two things are mutually exclusive? Especially for my iot things, I need to pass dhcp-options (vendor-specifics, dns, time, etc.).

How can I have a different domains in use across my various subnets, while retaining option codes and dhcp range/start/duration settings?

2

I can get the second instance to co-exist- I was missing the option instance 'xxx' in each of the dhcp blocks (and added a name to the default/OG dnsmasq block). But, clients on the iot network don't show with the expanded domain name:

DELL-LT5520                192.168.30.100
mac-mini.home.fqdn.com     192.168.1.180

when what I'm expecting to see is:

DELL-LT5520.iot.fqdn.com   192.168.30.100
mac-mini.home.fqdn.com     192.168.1.180

If I run nslookup DELL-LT5520.iot.fqdn.com from the router's terminal, it comes back NXDOMAIN. I do see where the domain is handed out by dhcp to the client in the syslog, and ipconfig on the laptop does show the iot.fqdn.com domain... Router's /etc/resolv.conf ends up having either search home.fqdn.com or search iot.fqdn.com, but not both domains at the same time. Feel like I'm close, but missing something simple.

3

The main dnsmasq instance would need to know to forward iot.fqdn.com and 30.168.192.in-addr.arpa queries to 192.168.30.1.