I have been running opsense for about 3 years and it has performed well for me. I have been using ISC DHCPv4 to distribute IPv4 addresses (I use SLACC for IPv6). When I tried to migrate to DNSmasq using the documentation at https://docs.opnsense.org/manual/dnsmasq.html#dnsmasq-dns-dhcp , it seems to start the service up just fine, but no DHCP addresses are distributed. Here is snip of my log file:
2026-03-29T00:32:58-05:00Informationaldnsmasq-dhcp IPv6 router advertisement enabled
2026-03-29T00:32:58-05:00Informationaldnsmasq-dhcp DHCP, IP range 192.168.74.2 -- 192.168.74.210, lease time 1d
2026-03-29T00:32:58-05:00Informationaldnsmasq configured with trust anchor for <root> keytag 20326
2026-03-29T00:32:58-05:00Informationaldnsmasq configured with trust anchor for <root> keytag 38696
2026-03-29T00:32:58-05:00Informationaldnsmasq DNSSEC validation enabled
2026-03-29T00:32:58-05:00Informationaldnsmasq compile time options: IPv6 GNU-getopt no-DBus no-UBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset no-nftset auth DNSSEC loop-detect no-inotify dumpfile
2026-03-29T00:32:58-05:00Informationaldnsmasq started, version 2.92 DNS disabled
I don't see some of the options listed in the documentation to turn on more debugging so I have not been able to do that.
From the docs:
Log DHCP options and tags
Extra logging for DHCP, log all the options sent to DHCP clients and the tags used to determine them.
Any ideas where I can start to debug this?
Just keep in mind any devices currently with IPs from ISC won't request a new IP until their current lease expires, and if you have a long lease time set, then DNSmasq won't appear to hand out any IPs for several days. An easy way to test is to make sure ISC is disabled and DNSmasq is enabled, and then manually release and renew an IP on a device.