KVM And Bridge Network Definition On Ubuntu

If you want to access the services on your KVM machines from Internet, it is most likely that you would need a bridge network interface. Let’s see how you can define a bridge network on Ubuntu.

First of all we will install the bridge-util package. This package will allow us to use the bridge interface.

sudo apt-get install bridge-utils

Now we can define our bridge in the interfaces file /etc/network/interfaces.

Depending on the ip assignment your are using we have 2 different configuration. If you are using static IPs:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual

auto br0
iface br0 inet static
address 192.168.7.60
network 192.168.7.0
netmask 255.255.255.0
broadcast 192.168.0.255
gateway 192.168.0.1
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off

If you are using DHCP then,

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off

We need to restart the networking service to be able to use the new settings.
We can use brtlcl command to check the newly create bridge interface. If everything worked as expected. you would see a similar output.

root@advance:~$ brctl show
bridge name    bridge id            STP enabled    interfaces
br0            8000.0023542177b9    no             eth0
                                                   vnet1
vnet0          8000.000000000000    yes

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1. How do you protect your SOHO (Small Office / Home Office ) network?