There were no plans for migrating the existing DHCP data to Kea as far as I now.
DHCPd opens a raw interface on all network interfaces. I don't think it is possible (at least with ISC DHCPd) to use two different DHCP daemons on one host simultaneously.
Kea and the old client can run in parallel on different vlans. Simply disable the old server on a vlan, copy all reservations/useful data to a text editor, go to Kea and set up the vlan in Subnets, add the Reservations, then to Settings to have Kea run on the interface.Should there be a need, disable Kea on the interface and reenable it on the other side.
Quote from: bimbar on February 01, 2024, 10:37:37 amDHCPd opens a raw interface on all network interfaces. I don't think it is possible (at least with ISC DHCPd) to use two different DHCP daemons on one host simultaneously.Correct for ISC-DHCP.
To the original question -- You'll need adjust your ruleset for UDP 67 & 68 on whichever interface(s) you expect to support. Apparently, OPNsense automatically sets up a rule for ISC dhcpd when it's enabled on an interface, but not for KEA dhcpd. (In the logging, the ISC rule shows up with the label "allow access to DHCP server").
opnsense-patch b1685d8
I was about to make the switch in my home lab when I found you cannot even serve the domain name to clients. Sorry, that is not going to fly.
I tried using kea without luck so far... Even though I disabled the ISC server on my vlan 630, stopped and started ISC to make sure it frees up the listening on port 67 on 192.168.63.1 but kea still complains it's unable to start properlyCode: [Select]WARN [kea-dhcp4.dhcpsrv.0x83359d000] DHCPSRV_OPEN_SOCKET_FAIL failed to open socket: Failed to open socket on interface ix1_vlan630, reason: failed to bind fallback socket to address 192.168.63.1, port 67, reason: Address already in use - is another DHCP server running? Checking netstat, I see *:67 so I guess ISC is listening on *:67 and prevents kea from running side-by-side.Still trying to see if there is a way around this...
WARN [kea-dhcp4.dhcpsrv.0x83359d000] DHCPSRV_OPEN_SOCKET_FAIL failed to open socket: Failed to open socket on interface ix1_vlan630, reason: failed to bind fallback socket to address 192.168.63.1, port 67, reason: Address already in use - is another DHCP server running?