[Kea-users] Help converting working ISC DHCP (Option 125 w/ suboption 193) to Kea

[Darren Ankney]

Hello,

I am not able to reproduce the error you receive on Kea start with
2.6.3 or 3.0.0.  Are you running an older version of Kea perhaps?  The
attached configuration starts on both versions i mentioned for me.
Note that I didn't send any traffic to the Kea server.  Just started
it.

Thank you,
Darren Ankney

On Sun, Sep 28, 2025 at 11:49 AM BruckyNetworks via Kea-users
<kea-users at lists.isc.org> wrote:
>
> Hi all,
>
> I’m attempting to migrate from ISC DHCP to Kea DHCP and failing badly. I am after some assistance translating a small, working ISC config into Kea.
>
> What the set up is successfully doing in ISC -
>
> Match on Option 61 (client-id) substring: offset 11, length 11 → "SERIALSTRING".
>
>
> Return Option 125 with a vendor suboption 193 (binary blob).
>
>
> Standard subnet options (router + DNS).
>
>
> Pool restricted to clients matching the class.
>
>
>
> Working ISC DHCP (simplified)
> ```
> # Define BBF Option 193 space
> option space BBF code width 1 length width 2;
>
> # Encapsulate Option 193 into Option 125
> option bbf-pma-info code 125 = encapsulation BBF;
>
> # Match Option 61 (client-id) substring for the serial at offset 11, length 11
> class "device-by-duid" {
>   match if substring(option dhcp-client-identifier, 11, 11) = "SERIALSTRING";
>   option bbf-pma-info 00:00:0d:e9:0c:c1:0a:10:04:ac:1f:5a:31:14:02:11:d7;
> }
>
> subnet 192.168.50.0 netmask 255.255.255.240 {
>   option routers 192.168.50.1;
>   option domain-name-servers 1.1.1.1;
>
>   pool {
>     allow members of "device-by-duid";
>     range 192.168.50.6 192.168.50.10;
>   }
> }
> ```
>
> This works and the ISC server matches Option 61 as above and replies with Option 125 carrying a suboption 193 that contains the shown binary value. Then I get an IP address assigned.
>
> Attempted Kea DHCP config I've tried -
>
> ```
> {
>   "Dhcp4": {
>     "interfaces-config": {
>       "interfaces": [ "ens192.4093/192.168.50.1" ],
>       "dhcp-socket-type": "udp"
>     },
>
>     "lease-database": { "type": "memfile", "persist": true },
>
>     "option-def": [
>       {
>         "name": "bbf-pma-info",
>         "code": 193,
>         "space": "vendor-44949",
>         "type": "binary"
>       }
>     ],
>
>     "client-classes": [
>       {
>         "name": "device-by-duid",
>         "test": "substring(option[61].text, 11, 11) == 'SERIALSTRING'",
>         "option-data": [
>           { "name": "vivso-suboptions", "data": "44949" },
>           {
>             "name": "bbf-pma-info",
>             "space": "vendor-44949",
>             "data": "00000de90cc10a1004ac1f5a31140211d7",
>             "always-send": true
>           }
>         ]
>       }
>     ],
>
>     "subnet4": [
>       {
>         "subnet": "192.168.50.0/28",
>         "pools": [
>           { "pool": "192.168.50.6 - 192.168.50.10", "client-class": "device-by-duid" }
>         ],
>         "option-data": [
>           { "name": "routers", "data": "192.168.50.1" },
>           { "name": "domain-name-servers", "data": "1.1.1.1" }
>         ]
>       }
>     ]
>   }
> }
> ```
>
> Error from Kea on load:
> definition for option 'vendor-44949.bbf-pma-info' does not exist
>
> I've tried so many different variations and also asked every AI bot going but I just don't seem to be able to crack the KEA equivalent of what I have working in ISC.
>
> So what I am after please -
>
> What idiotic thing am I doing/not doing?
>
>
> What is the correct Kea configuration to replicate the ISC behaviour (Option 125 with vendor suboption 193)?
>
>
> Do I need to structure the option-def / option-data differently for vendor suboptions?
>
>
> A minimal working Kea example for this would be super greatly appreciated.
>
>
>
> Cheers all, happy to answer any further questions if needed.
> --
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>
> To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users.
> Kea-users at lists.isc.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: kea-dhcp4.json
Type: application/json
Size: 1546 bytes
Desc: not available
URL: <https://lists.isc.org/pipermail/kea-users/attachments/20251001/c496a16d/attachment.json>