Libvirt virsh : Error starting network, cannot execute binary /usr/sbin/iptables

[Pascal]

Hi,

I am a bit lost and hope someone can help me. I am running Debian 
bookworm (testing) with last updates.

$ sudo apt policy libvirt-daemon
libvirt-daemon:
   Installé : 8.5.0-1
   Candidat : 8.5.0-1
  Table de version :
  *** 8.5.0-1 100
         100 /var/lib/dpkg/status


I am unable to start default network , and get an error related to 
iptables :

$ sudo virsh net-start default
erreur :Impossible de démarrer le réseau default
erreur :internal error: Failed to apply firewall rules 
/usr/sbin/iptables -w --table filter --list-rules: libvirt:  erreur : 
cannot execute binary /usr/sbin/iptables: Aucun fichier ou dossier de ce 
type

Sorry for the french, it says "impossible to start default network" and 
"no such file or folder" at the end.

It is true I removed iptables because I want to use only nftables (I 
removed both ufw and iptables packages (apt remove), and enabled the 
nftables service before error raises). Before this, all was fine, but 
when I enabled nftables, all VMs disapeared  from virt-manager).

I uninstalled KVM related packages and reinstalled, still the same.

I also installed back iptables, but strangely I still get the same 
error, although binary /usr/sbin/iptables is there.

I tried many things with no luck, restarted libvirtd service, recreated 
the network, etc...

Has anyone some idea about what is happening here ? is there some 
incompatibility with nftables (firewalld service is disabled) and libvirt ?

Thank you,
Pascal