Network interfaces vibr0 and vibr0-nic

I can guess by the names that they are probably “virtual bridges”, but what exactly are they and, more importantly, why has Fedora 33 Workstation configured them without my knowledge? I have only recently noticed that they exist, and I don’t know how long they have existed.


I found this on Stack exchange.

I don’t overtly use virtual machines, so I still don’t understand why they have been created on my system.

This happens by installing libvirt.
virbr0 is the name of the virtual network created by libvirt
virbr0-nic is the adapter in the virtual network.

By creating a virtual machine the default network option is NAT and so virtual machines use the virbr0 as the network, independent from your host network.

If you use bridged connection you can choose the local adapter. It will be like a switch and you get an IP in the same range as your local network. No need for virbr0 then.

If you want to configure the virtual network user interface you could do this with virsh


Ok, but I have not knowingly installed libvirt, either. Maybe it came as excess baggage with something else. IDK, but I’ll check when I get back to that host.

Thanks for your response.

Hi blueshurricane4 and @ilikelinux

I think this happens by default now, as I’ve just a done a fresh install and it comes with gnome-boxes; which I would suspect requires libvirt and the 2 interfaces are present.

Thanks Tom.

> sudo rpm -q -f /etc/libvirt/qemu/networks/default.xml

> sudo dnf -q repoquery --whatrequires libvirt-daemon-config-network

> sudo dnf -q group info "Fedora Workstation" | grep -e GNOME
   GNOME Desktop Environment

> sudo dnf -q group info "GNOME Desktop Environment" | grep -e gnome-boxes

Commit - rpms/gnome-boxes - 85c65b668c88782b700119148920fd63c3836e27 -


That interface has been showing up for at least since version 30.

It is a virtual device and interface, and as has already been said is used by any VMs you might configure. I use bridging mode on my VMs and the virbr0 device so they have direct connection to the host machine, although on a different subnet. virbr0 resides as IP on all my machines. The VM has access to the internet since the default config for the host is forwarding and NAT for traffic from the VM.

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That must be it. Thank you.

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I am disappointed in myself that I have never noticed it, then.

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