Linux: Create Network Bridge For KVM

The bridged network is a dedicated network interface to a virtual machine that helps virtual machines to connect outside the host machine.

Let us list the available network connections.COPY

nmcli connection show

Output:

NAME                UUID                                  TYPE      DEVICE
Wired connection 1  fbbdd6f9-0970-354e-8693-ff8050a85c77  ethernet  enp0s3

Now, we will create a virtual bridge network br0 with the help of physical interface enp0s3.

sudo nmcli con add ifname br0 type bridge con-name br0

sudo nmcli con add type bridge-slave ifname enp0s3 master br0

Next, we will assign the IP address of the physical interface to the bridge interface as the Bridge network interface will act as the primary network interface of your host system.COPY

sudo nmcli con mod br0 ipv4.addresses 192.168.0.10/24

sudo nmcli con mod br0 ipv4.gateway 192.168.0.1

sudo nmcli con mod br0 ipv4.dns "8.8.8.8","192.168.0.1"

sudo nmcli con mod br0 ipv4.method manual

KVM requires a few additional network settings. So, set them.COPY

sudo nmcli con modify br0 bridge.stp no

sudo nmcli con modify br0 bridge.forward-delay 0

Disable the physical interface and enable the network bridge.COPY

sudo nmcli con down "Wired connection 1" && sudo nmcli con up br0

Run the above command in the system terminal as you may lose SSH sessions when running them remotely.

Finally, check the network connections.COPY

sudo nmcli con show

Output:

NAME                 UUID                                  TYPE      DEVICE
br0                  ee117099-4935-4dde-a1f5-4981b0d9585e  bridge    br0
bridge-slave-enp0s3  492b5c81-e59d-4150-9b24-0348cd0dd87c  ethernet  enp0s3
Wired connection 1   fbbdd6f9-0970-354e-8693-ff8050a85c77  ethernet  --

By: Raj