19.2.13. Setting up a network connection

NAT networking will cover most requirements for the Platform, but in some cases, for example, with local nfsroot, bridging will be required instead. The network configuration on the host Linux machine must be updated to allow this. There are several stages to this:

  1. Make sure that you have installed the brctl utility on your system.


    ARM recommends using the standard Linux bridge utilities included in the Linux distribution. For more information about the Linux bridge utilities see:


  2. Disable the current ethernet device (eth0 in this case) using:

    # ifconfig eth0 down


    You must turn off Network Manager to do this. It does not support advanced networking options such as bridging.

  3. To turn off Network Manager, use:

    /etc/init.d/NetworkManager stop


    Turning off Network Manager can differ from system to system. Check your OS documentation for how to disable Network Manager.

  4. Add a new virtual device (the <bridge_name>, in this case tap0) using:

    # ip tuntap add dev tap0 mode tap
  5. Add a new bridge device using eth0 and tap0, and enable it, using:

    # brctl addbr br0
    # brctl addif br0 eth0
    # brctl addif br0 tap0
  6. Enable the new bridge device and request an IP address using DHCP using:

    # ifconfig br0 up
    # dhclient br0
  7. This new network device br0 should work like the existing eth0 device, but will share the physical network connection between eth0 and tap0. The tap0 virtual device is used by the model to access the network.

  8. Run the model with the command-line options --network=bridged

    --network-bridge=<bridge name> 

    where <bridge_name> = tap0.

  9. Check that the network facility is present by pinging any suitable website.

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