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6.3. Using the NetworkManager Command Line Tool, nmcli

To create a bridge, with name bridge-br0, issue a command as follows:
~]$ nmcli con add type bridge ifname br0
Connection 'bridge-br0' (79cf6a3e-0310-4a78-b759-bda1cc3eef8d) successfully added.
If no interface name is specified, the name will default to bridge, bridge-1, bridge-2, and so on.
To view the connections, issue the following command:
~]$ nmcli con show conf
NAME        UUID                                 TYPE           TIMESTAMP-REAL
eth0        4d5c449a-a6c5-451c-8206-3c9a4ec88bca 802-3-ethernet Mon 21 Oct 2013 16:01:53 BST
bridge-br0  79cf6a3e-0310-4a78-b759-bda1cc3eef8d bridge         never
Spanning tree protocol (STP) according to the IEEE 802.1D standard is enabled by default. To disable STP for this bridge, issue a command as follows:
~]$ nmcli con bridge-br0 stp no
To re-enable 802.1D STP for this bridge, issue a command as follows:
~]$ nmcli con bridge-br0 stp yes
The default bridge priority for 802.1D STP is 32768. The lower number is preferred in root bridge selection. For example, a bridge with priority of 28672 would be selected as the root bridge in preference to a bridge with priority value of 32768 (the default). To create a bridge with a non-default value, issue a command as follows:
~]$ nmcli con add type bridge ifname br5 stp yes priority 28672
Connection 'bridge-br5' (86b83ad3-b466-4795-aeb6-4a66eb1856c7) successfully added.
The allowed values are in the range 0 to 65535, but can only be set in multiples of 4096.
To change the bridge priority of an existing bridge to a non-default value, issue a command in the following format:
~]$ nmcli connection modify bridge-br5 bridge.priority 36864
The allowed values are in the range 0 to 65535, but can only be set in multiples of 4096.
Further options for 802.1D STP are listed in the bridge section of the nmcli(1) man page.
To add, or enslave an interface, for example eth1, to the bridge bridge-br0, issue a command as follows:
~]$ nmcli con add type bridge-slave ifname eth1 master bridge-br0
Connection 'bridge-slave-eth1' (70ffae80-7428-4d9c-8cbd-2e35de72476e) successfully added.
At time of writing, nmcli only supports Ethernet slaves.
To change a value using interactive mode, issue the following command:
~]$ nmcli connection edit bridge-br0
You will be placed at the nmcli prompt.
nmcli> set bridge.priority 4096
nmcli> save
Connection 'bridge-br0' (79cf6a3e-0310-4a78-b759-bda1cc3eef8d) successfully saved.
nmcli> quit
See Section 2.4, “Using the NetworkManager Command Line Tool, nmcli” for an introduction to nmcli