Re: Managing interface with random MAC address

[Kay Sievers <kay sievers vrfy org>]

On Thu, Mar 5, 2009 at 22:38, Russ Dill <russ dill gmail com> wrote:
> On Thu, Mar 5, 2009 at 2:19 PM, Dan Williams <dcbw redhat com> wrote:
>> On Thu, 2009-03-05 at 12:47 -0700, Russ Dill wrote:
>>> On Thu, Mar 5, 2009 at 5:33 AM, 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?
>>>
>>> The serial number is zero. The unique identifier is that its usb0.
>>
>> And there's the problem.  It won't always be usb0.  If you have two, it
>> could be usb1.  Thus there isn't any unique identifier.
>
> In my situation, I don't care. Currently, if I want this to work, I
> have to change the hardware address in the network manager settings
> every single time I reboot the board. The limitation of only being
> able to plug in one at a time seems rather minor to me.
>>
>>> > 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.
>>>
>>> I may have got my managed/unmanaged terminology confused. Right now,
>>> NetworkManager handles all devices not listed int
>>> /etc/network/interfaces. I have two wired devices, one is my permanent
>>> eth0. eth0 I want nm to manage. The other is the beagle board.

Just to throw more stuff into the "config matched by MAC address"
thing, there are systems where several interfaces have the same MAC
address, some para-virtualized environments create two identical
interfaces, which are only different in the bus they belong to, and
stuff like the PlayStation3 creates wired and wireless interfaces with
the same MAC address. I've run into all that with the udev persistent
net interface rule-generator. :)

Kay