Re: Managing interface with random MAC address

[Kay Sievers <kay sievers vrfy org>]

On Thu, Mar 5, 2009 at 13:33, Dan Williams <dcbw redhat com> wrote:
> On Thu, 2009-03-05 at 01:25 -0700, Russ Dill wrote:
>> I have an embedded device known as a beagle board that draws power
>> from my USB port (shows up as usb0). When it boots, it presents itself
>> as a USB ethernet device. I want to share my connection with the
>> device from network manager.
>>
>> Two problems: The first is that network manager sees an unmanaged
>> device and tries to obtain an IP address, the second, I can't seem to
>> setup an automatic share my connection connection since every time the
>> board boots, it has a different hardware address. Any tips?
>
> What is the USB serial number of the device?  The core problem here is
> that if there's no unique identifier for the device, there's no way to
> lock a specific connection to that device, and thus any generic Wired
> connection will be used instead.
>
> Run "lsusb -v" and look for the iSerial field; is that field something
> other than 0?  Do other beagle boards present other serial numbers?
>
> Do you want to keep the wired device unmanaged and ignored by
> NetworkManager?  You said "sees an unmanaged device and tries to obtain
> an IP address", but NM should be ignoring unmanaged devices.  However,
> that mechanism depends on HAL UDIs and thus the random MAC address may
> well be confusing it.

A random MAC address is defined by a bit in the MAC address itself.
Maybe these devices should be special handled. At least the MAC should
not be stored somewhere on the system.

The udev persistent netif name rule generator does this:
  # do not use "locally administered" MAC address
  ENV{MATCHADDR}=="?[2367abef]:*", ENV{MATCHADDR}=""

Kay