in Developer Experience

Resolving VirtualBox-based Vagrant boxes IP collisions

How to solve collisions of VirtualBox with virtual bridges on Fedora (e.g. when running Vagrant).

The problem occurs when trying to start VirtualBox-based Vagrant box due to IP collision with such a bridge. Vagrant would report something along the lines:

The specified host network collides with a non-hostonly network!
This will cause your specified IP to be inaccessible. Please change
the IP or name of your host only network so that it no longer matches
that of a bridged or non-hostonly network.

Vagrant actually runs /usr/bin/VBoxManage list bridgedifs command to determine the collision, but you will see it with ip addr show command as well.

$ /usr/bin/VBoxManage list bridgedifs | grep "10.1.2.1"
IPAddress:       10.1.2.1

One of the virtual bridges occupies 10.1.2.1 address which is used by VirtualBox. In my case it’s virbr3.

To get rid of the interface you need to first bring it down and then remove:

$ sudo ip link set virbr3 down
$ sudo brctl delbr virbr3

Of course make sure you don’t need the interface anymore before doing that.

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