I get an odd interaction between kea and libvirt's networking when I
reboot my computer.

The system comes up more or less as usual. Kea is running. Libvirt
tries to bring the virtual network up, but fails:

root@hawk:~# journalctl -b | grep dnsmasq
Apr 12 14:43:58 hawk dnsmasq[2652]: failed to bind DHCP server socket: Address already in use
Apr 12 14:43:58 hawk dnsmasq[2652]: FAILED to start up
Apr 12 14:43:58 hawk libvirtd[2348]: internal error: Child process (VIR_BRIDGE_NAME=virbr0 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper) unexpected exit status 2:
dnsmasq: failed to bind DHCP server socket: Address already in use
Apr 12 15:34:07 hawk dnsmasq[4352]: failed to bind DHCP server socket: Address already in use
Apr 12 15:34:07 hawk dnsmasq[4352]: FAILED to start up
Apr 12 15:34:07 hawk libvirtd[4272]: internal error: Child process (VIR_BRIDGE_NAME=virbr0 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper) unexpected exit status 2:
dnsmasq: failed to bind DHCP server socket: Address already in use

I'm not sure to which address the error message refers. Only lo and
enp3s0 are running even after manually issuing "virsh net-start
default".

If I shut kea-dhcp4-server.service down, I can then start the virtual
network manually. I can then re-start kea-dhcp4-server.service.


--
Does anybody read signatures any more?

https://charlescurley.com
https://charlescurley.com/blog/

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Sun, Apr 12, 2026 at 18:18 Charles Curley <
charlescurley@charlescurley.com> wrote:

I get an odd interaction between kea and libvirt's networking when I
reboot my computer.

The system comes up more or less as usual. Kea is running. Libvirt
tries to bring the virtual network up, but fails:

root@hawk:~# journalctl -b | grep dnsmasq
Apr 12 14:43:58 hawk dnsmasq[2652]: failed to bind DHCP server socket: Address already in use
Apr 12 14:43:58 hawk dnsmasq[2652]: FAILED to start up
Apr 12 14:43:58 hawk libvirtd[2348]: internal error: Child process (VIR_BRIDGE_NAME=virbr0 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper) unexpected exit status 2:
dnsmasq: failed to bind DHCP server socket: Address already in use
Apr 12 15:34:07 hawk dnsmasq[4352]: failed to bind DHCP server socket: Address already in use
Apr 12 15:34:07 hawk dnsmasq[4352]: FAILED to start up
Apr 12 15:34:07 hawk libvirtd[4272]: internal error: Child process (VIR_BRIDGE_NAME=virbr0 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper) unexpected exit status 2:
dnsmasq: failed to bind DHCP server socket: Address already in use

I'm not sure to which address the error message refers. Only lo and
enp3s0 are running even after manually issuing "virsh net-start
default".

If I shut kea-dhcp4-server.service down, I can then start the virtual
network manually. I can then re-start kea-dhcp4-server.service.

--
Does anybody read signatures any more?

https://charlescurley.com
https://charlescurley.com/blog/

without being able to see logs i would bet a shiny nickel on libvirt's own
dhcp server conflicting with kea. i believe you can destroy the default libvirt network which should allow you to run kea to handle dhcp for you .
HTH
// jkl

<https://charlescurley.com/blog/>

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)