[kea-dev] Issues with the REJECT class

[Philip Prindeville]

Hi,

I'm trying to get the REJECT class working in OpenWRT (backported the commits in 4110 to 3.0.2) and built that.

The synthesized config looks like:

     1	{
     2	  "Dhcp4": {
     3	    "lease-database": {
     4	      "type": "memfile",
     5	      "persist": true,
     6	      "name": "/var/lib/kea/kea-leases4.csv",
     7	      "lfc-interval": 900,
     8	      "max-row-errors": 1
     9	    },
    10	    "interfaces-config": {
    11	      "interfaces": [
    12	        "eth1.3",
    13	        "eth1.4"
    14	      ],
    15	      "client-classes": [
    16	        {
    17	          "name": "REJECT",
    18	          "test": "not member('KNOWN')"
    19	        }
    20	      ],
...
   701	    "reservations-in-subnet": true
   702	  }
   703	}


And I get:

May 31 20:48:15 OpenWrt2 kea-dhcp4[30682]: 2026-05-31 20:48:15.239 INFO  [kea-dhcp4.dhcp4/30682.139821524071952] DHCP4_STARTING Kea DHCPv4 server version 3.0.2 (stable) starting
May 31 20:48:15 OpenWrt2 kea-dhcp4[30682]: 2026-05-31 20:48:15.249 ERROR [kea-dhcp4.dhcp4/30682.139821524071952] DHCP4_CONFIG_LOAD_FAIL configuration error using file: /etc/kea/kea-dhcp4.conf, reason: /etc/kea/kea-dhcp4.conf:15.7-22: got unexpected keyword "client-classes" in interfaces-config map.
May 31 20:48:15 OpenWrt2 kea-dhcp4[30682]: 2026-05-31 20:48:15.250 ERROR [kea-dhcp4.dhcp4/30682.139821524071952] DHCP4_INIT_FAIL failed to initialize Kea server: configuration error using file '/etc/kea/kea-dhcp4.conf': /etc/kea/kea-dhcp4.conf:15.7-22: got unexpected keyword "client-classes" in interfaces-config map.


On a per-subnet basis, I'm trying to reproduce the functionality of the "deny unknown-clients;" option in ISC-DHCP.

I want to DROP or REJECT unknown clients on a per-subnet basis.

What am I missing here?

Thanks,

-Philip