[Samba] Samba as Active Directory - Linux Client doesn't update DNS

[Tilo Lutz]

Hi
I'm playing with smaba the first time so please be patient with me.
I want to setup a small active directory on by Raspberry Pi 4 at home.
Actual my setup is:
-- Router (DHCP, Forward DNS)
\- Raspberry with Samba AD and Bind9 as DNS
Windows and Linux Clients:
DHCP from Router. The router is configured to annouce the Raspberry as DNS server.
I configure it as described at: https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_Domain_Controller
Standard behavior of the router is to put all DCHP clients into it's own domain with hostname.router. This is working fine.
The samba AD also provides DNS service for the domain .ad
DNS updates, Kerberos etc. is working fine. When a windows client joins the domain, hostname.ad is added to bind. The router will add it with hostname.router. Tha't exactly what I want. The host is reachable with hostname.router and hostname.ad.
Unfortunately, this is not working for a linux client. I used the realmd to join the active directory. It can access the domain, get users and groups but no dns entry is added to the bind9 server. I was able to add the client manually with samba-tool dns add.
To me it looks like the linux client never tried to register its dns entry.
So my question is: Do I expect something from the linux client that is not done by default?
How can I make the linux client to generate/update their DNS records, including IPv4 and IPv6?
Thank you very much,
Tilo