[Kea-users] DDNS doesn't update local zone

[Michael De Roover]

Hi Alessandro,

Out of curiosity, which platform is this misbehaving client running? While upgrading my own instances of ISC DHCP, I noticed (among a few other shamefully dated configurations), that one of my clients is / was also misbehaving. This is an Android phone running LineageOS 22.2 (official release).

I have since then examined my log files, where the client requests an address it had previously but is not allowed to have. The server responds with DHCPNAK, and DHCPOFFER for the configured static lease. The client ignores this response and DHCPREQUEST again for the erroneous address. Upon continued DHCPNAK, the client ignores the server and applies the wrong address, then complains that it doesn’t have Internet access.

In order to resolve that issue, as well as misbehaving connectivity check (though both have mysteriously gone away now on its own, always reassuring), I intend to build LineageOS from source myself. Additionally, I have made my internal web servers perform /generate_204 and DNS RPZ point connectivitycheck.gstatic.com to mine instead. In the build from source, I intend to just replace the Google address altogether. In addition, I want to pay close attention to the DHCP stack. It should not be ignoring what on the wire was multiple attempts to make the client behave, being promptly ignored by said client.

Best regards,
Michael De Roover

> On 10 Nov 2025, at 13:08, Alessandro Vesely <vesely at tana.it> wrote:
> 
> Hi,
> I recently upgraded to Devuan Excalibur, equivalent to Debian Trixie, and had some difficulty starting the Kea daemons. Now they're running.  However, a client somehow got a different IP than it had before.
> 
> The host name and PTR records still use the previous IP.
> 
> I tried to fix it by issuing dhclient -r/ dhclient.  As a result, I have several records showing the new IP in /var/lib/dhcp4.csv, but the DNS records are unchanged.
> 
> In kea-dhcp4 both enable-updates and ddns-send-updates are set to true.
> 
> In both kea-dhcp4.conf and kea-dhcp-ddns.conf I set debuglevel to 99, but, upon restarting, I only got the two lines
> 
> kea-dhcp4: INFO  [kea-dhcp4.commands.140267918301120] COMMAND_RECEIVED Received command 'config-set'
> 
> and
> 
> kea-dhcp-ddns: INFO  [kea-dhcp-ddns.dctl.140298412311744] DCTL_STARTING DhcpDdns starting, pid: 17117, version: 2.6.3 (stable)
> 
> 
> 
> Dhcp releases and subsequent discover, offer, request and ack are not logged.
> 
> 
> Is there a way to force the DNS to sync?
> 
> 
> Best
> Ale
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> 
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