KEA DHCP and DHCP Option 43

Networking & Firewalls
1

I’m on pfSense 2.8.1 and tried doing the DHCP Option 43 for Unifi adoption. But I’m using Kea DHCP and the ISC DHCP isn’t available anymore to switch back. Has a workaround been figured out or do we have to wait for Netgate to add the “Custom DHCP Option”?

Edit: Got some help from AI using JSON as follows…

Screenshot 2025-12-21 134120
Screenshot 2025-12-21 134120692×267 10.6 KB

2

We have it working, you need to enter the details in two places

Under Services - DHCP Server - Settings - Custom Configuation

{
“option-def”: [
{
“space”: “dhcp4”,
“name”: “unificontroller”,
“code”: 43,
“type”: “binary”
}
]
}

Under Services - DHCP Server - Select the Network - Custom Configuration

{
“option-data”: [
{
“name”: “unificontroller”,
“data”: “0104xxxxxxxx”
}
]
}

Data has the ip address of your unifi controller 0104 hex value of server

3

Hello, sorry to say but it’s not working!

I think because it say’s below the JSON input veld:

*JSON to be merged into the “subnet” section of the generated Kea DHCPv4 configuration.
The input must be a well formed JSON object and should not include the “subnet” key itself.
*
and also the JSON is not recognized ass valid json format.

The following input errors were detected:

  • Custom configuration is not a well formed JSON object.

:frowning:

4

It didn’t work because of the quotes. Copy and paste these instead.

{
  "option-def": [
    {
      "code": 43,
      "name": "unificontroller",
      "space": "dhcp4",
      "type": "binary"
    }
  ]
}

{
  "option-data": [
    {
      "data": "0104xxxxxxxx",
      "name": "unificontroller"
    }
  ]
}
1 Like
5

Thank for JohnF350KR and pjsayers.anotherit also xMAXIMUSx it works now fine.

I did the same as example by xMAXIMUSx and it works like a flawless

Alway keep my fingers crossed :slight_smile: