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

[Joop Boonen]

Hi Peter,

The Problem is, as it looks like. If there is no hostname reserveration. (flex-
id or hardware address etc).
The hostname-expr doesn't have any effect. 
Therefor no ddns entry is written in dns.

Regards,

Joop.

On Thursday, January 8, 2026 10:13:58 AM Central European Standard Time Peter 
Davies wrote:
> Hi Joop,
>    Could you try this "hostname-expr" in your ddns-tuning parameters:
> "hostname-expr" : "'vm-test-' +
> uint8totext(substring(option[50].hex,0,1)) + '-' +
> uint8totext(substring(option[50].hex,1,1)) + '-' +
> uint8totext(substring(option[50].hex,2,1)) + '-' +
> uint8totext(substring(option[50].hex,3,1))"
> You need not define a flex-id or load the flex-id hooks library if you
> do not use host reservations that depend on flex-ids's
> /Peter
> 
> On 06/01/2026 14.42, Peter Davies wrote:
> >  "hostname-expr" : "concat('vm-test-',addrtotext(option[50].hex))"