NetworkManager and bridging

Friday, 20, December 2013 Jim Perrin networking 6 Comments

In previous iterations of NetworkManager, it was really only useful if you were dealing with wireless networks. Anything involving a bridge meant removing the device from NetworkManager, and manually configuring the network.

A fair amount of work has been done to make NetworkManager more friendly to bridged devices, however it's still far from perfect.    My experiences so far:

The screenshot below should demonstrate the confusion to some extent. I wouldn't expect the 'Wired' connection to show up, as it's a slave to the bridge. Both the virbr0 and the vpn show as off, even though both are active and in use.

network-manager

At this point the best course of action for anyone who needs a bridge is simply to remove NetworkManager from the equation. Since this is already current practice, it's not really a deviation for folks tracking 6->7 differences.

6 thoughts on "NetworkManager and bridging"

  1. Mika Ilmaranta says:

    Have You been able to get bond devices up and running without NetworkManager?

    1. Jim Perrin says:

      I haven't tried bonds at all yet. I don't have any news on them to offer.

  2. Yogesh says:

    One can use NM to setup bridge:

    Here are steps
    1 Applications -> System Tools -> Settings -> Network
    2 Disable existing wired Network
    3 Add new bridge connection
    4 In popup dialog general tab ensure "Connect Auto" is checked
    5 "Bridged connections" Add
    6 In popup dialog general tab ensure "Connect Auto" is checked
    7 From Device MAC dropdown select MAC of your existing wired network ( which was disabled in step #2)
    8 Finish by clicking save on all the dialogs

    Bridge should be working now except (as you wrote icon shows wrong state)

  3. Is Bridging nessasary when creating vlans in libvirt ? or does libvirt create the bridges itzelf ?

  4. serg says:

    Open the Terminal app
    Get info about the current connection:
    nmcli con show
    Add a new bridge:
    nmcli con add type bridge ifname br0
    Create a slave interface:
    nmcli con add type bridge-slave ifname eno1 master br0
    Turn on br0:
    nmcli con up br0

    https://www.cyberciti.biz/faq/how-to-add-network-bridge-with-nmcli-networkmanager-on-linux/

  5. Akemi Yagi says:

    There is a CentOS wiki article, "Setting up a network bridge using nmcli on CentOS 7"

    https://wiki.centos.org/TipsAndTricks/BridgeAndNmcli

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