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virsh / Failed to start network default

I've been scouring google for the past day trying to figure out why I can't create a default network for my linux guest. One source says the iptables error is harmless, but I still can't create a default network. What's going on here?

the default.xml didn't even exist on my filesystem, so I had to copy it from a forum.

Code:

# pwd

/usr/share/libvirt/networking



# virsh net-undefine default

Network default has been undefined



# virsh net-destroy default

error: failed to get network 'default'

error: Network not found: no network with matching name 'default'



# virsh net-list

 Name  State  Autostart  Persistent

----------------------------------------



# cat default.xml

<network>

  <name>default</name>

  <uuid>afd4e923-66cb-45ca-9120-1e46e72899a3</uuid>

  <forward mode='nat'>

    <nat>

      <port start='1024' end='65535'/>

    </nat>

  </forward>

  <bridge name='virbr0' stp='on' delay='0'/>

  <ip address='192.168.122.1' netmask='255.255.255.0'>

    <dhcp>

      <range start='192.168.122.2' end='192.168.122.254'/>

    </dhcp>

  </ip>

</network>



# virsh net-define default.xml

Network default defined from default.xml



# virsh net-autostart default

Network default marked as autostarted



# virsh net-start default

error: Failed to start network default

error: internal error: Failed to apply firewall rules /sbin/iptables -w --table filter --insert LIBVIRT_INP --in-interface virbr0 --protocol tcp --destination-port 67 --jump ACCEPT: iptables: No chain/target/match by that name.

Code:

# uname -a

Linux user-pc 5.3.0-45-generic #37-Ubuntu SMP Thu Mar 26 20:41:27 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux



# cat /etc/issue

Ubuntu 19.10 \n \l

Found the magic bullet. I think I just had to restart the libvertd service...

Code:

virsh net-undefine default

virsh net-destroy default

virsh net-list

systemctl enable --now libvirtd

systemctl enable virtlogd.socket

systemctl restart libvirtd.service

cat default.xml

virsh net-define default.xml

virsh net-autostart default

virsh net-start default

Eight months later this post saved my day! No, what am I saying, my week!

virsh --version
6.7.0

Running on Debian 10.
Just a note: my default.xml was located in the directory /etc/libvirt/qemu/networks/, and it was erased by the command virsh net-destroy default.
Luckily I had an old one saved as /etc/libvirt/qemu/networks/default.xml.dpkg-old, which only differed from the original one by the interface's UUID and mac address.
So I only had to copy it into /etc/libvirt/qemu/networks/default.xml and run:

virsh net-define /etc/libvirt/qemu/networks/default.xml
virsh net-autostart default
virsh net-start default

to have the network back online!

Should it be handy to someone else, I'm copying it's content here:



<network>
<name>default</name>
<uuid>df2e3516-fd39-9ac5-4df2-a6125fd75c7c</uuid>
<forward mode='nat'/>
<bridge name='virbr0' stp='on' delay='0'/>
<mac address='a0:47:01:d5:85:c6'/>
<ip address='192.168.0.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.0.2' end='192.168.0.254'/>
</dhcp>
</ip>
</network>