[Kea-users] Ddns not Updated when hostname is assigned via hw-address when using hook libdhcp_ddns_tuning.so

[Joop Boonen]

Hi Peter,

Thank you very much.

"ddns-replace-client-name": "always"
was the solution.

Regards,

Joop.

On Thursday, January 8, 2026 2:47:19 PM Central European Standard Time Peter 
Davies wrote:
>   Hi Joop,
>     What value do you have "ddns-replace-client-name" configured to?
> 
> Sending a DHCPDiscover with no hostname (option 12), I see the hostname
> created
> by the ddns-tuning hook being sent back to the client and forwarded to
> kea-dhcp-ddns.
> 
> Using "ddns-replace-client-name": "always", and the previous
> "hostname-expr".
> 
> --- paste---
> msg_type=DHCPACK (5), trans_id=0xa47b2617, secs=0, flags=0x0,
> yiaddr=192.168.20.100, giaddr=192.168.20.1,
> options:
>    type=001, len=004: 4294967040 (uint32)
>    type=003, len=004: 192.168.20.1
>    type=012, len=034: "vm-test-192-168-20-100.example.com" (string)
>    type=051, len=004: 7200 (uint32)
>    type=053, len=001: 5 (uint8)
>    type=054, len=004: 192.168.10.1 (ipv4-address)
>    type=082, len=016:,
> options:
>      type=001, len=014: 76:65:74:68:2d:72:65:6c:61:79:2d:63:6c:69
> 'veth-relay-cli'
> ...
> 2026-01-08 13:42:54.089 DEBUG [kea-dhcp4.dhcpsrv/143967.139899928512384]
> DHCPSRV_DHCP_DDNS_NCR_SENT NameChangeRequest sent to kea-dhcp-ddns:
> Type: 0 (CHG_ADD)
> Forward Change: yes
> Reverse Change: yes
> FQDN: [vm-test-192-168-20-100.example.com.]
> IP Address: [192.168.20.100]
> DHCID:
> [000001F868E6B22D81DAFE0535549E8A960F055026EA04BF615B53D5A1CE0479A4CD98]
> Lease Expires On: 20260108142254
> Lease Length: 2400
> Conflict Resolution Mode: no-check-with-dhcid
> ---/paste---
> 
> /Peter