[CentOS] Trying to override MAC addr

Thu Aug 21 15:53:33 UTC 2014
Digimer <lists at alteeve.ca>

On 21/08/14 11:43 AM, Robert Moskowitz wrote:
> On 08/21/2014 11:31 AM, Digimer wrote:
>> On 21/08/14 11:25 AM, Robert Moskowitz wrote:
>>> On 08/21/2014 10:56 AM, Reindl Harald wrote:
>>>> Am 21.08.2014 um 16:43 schrieb Robert Moskowitz:
>>>>> On 08/21/2014 10:32 AM, m.roth at 5-cent.us wrote:
>>>>>> Keith Keller wrote:
>>>>>>> On 2014-08-21, John R Pierce <pierce at hogranch.com> wrote:
>>>>>>>> On 8/21/2014 7:09 AM, Robert Moskowitz wrote:
>>>>>>>>> I am trying to override the mac addr.
>>>>>>>> pretty sure you need to use NIC model specific utilities to do this,
>>>>>>>> ifcfg-ethN won't do it.   the hwaddr= in there is for finding the nic,
>>>>>>>> not for reprogramming it.
>>>>>>> ifconfig claims to support it:
>>>>>>>             hw class address
>>>>>> <snip>
>>>>>> Also, don't forget /etc/udev/rules.d/70-persistant-net.rules
>>>>> I can't forget what I don't know.  please point me to description of
>>>>> these rules?
>>>> just look at the file
>>>> in the past and on CentOS before RHEL7 it was to assign MAC/device-names
>>>> at boot, on recent Redhat based systems just remove it and stick with
>>>> place both in the ifcfg-files while disable biosdevname and systemd
>>>> devicenames at boot
>>>> both, that udev rules and what i explained you may collide or at least
>>>> you need to change the MAC there too to not confuse the configs
>>> I worked a bit on this.  I no longer have the MAC or HW addrs in
>>> ifcfg-eth0.  Only in /etc/udev/rules.d/70-persistent-net.rules, and only
>>> for name=eth0:
>>> # net device ()
>>> SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*",
>>> ATTR{address}=="02:67:15:00:01:79", ATTR{type}=="1", KERNEL=="eth*",
>>> NAME="eth0"
>>> but on reboot, I get the error:
>>> Bringing up interface eth0:  Device eth0 does not seem to be present,
>>> delaying initialization.
>>> [FAILED]
>>> and the ethernet comes up as eth1 and the eth1 line is added to
>>> /etc/udev/rules.d/70-persistent-net.rules
>>> Almost as if there is something else that needs changing.
>> Note that you still have to tell the OS "See this real MAC address?
>> Change it to this new MAC address". Shy of reprogramming the NIC
>> directly, you will almost certainly need to continue to reference the
>> real MAC address.
> So that means I need to find the full syntax of this rule.
> Oh, and there is no real MAC address and that MIGHT be part of the
> problem.  Many armv7 cards do not have eeprom so no MAC address.  In
> this case the kernel is creating the MAC address as local scope based on
> the SID.  So somewhere this is happening, and Hans (who maintains the
> uboot Allwinner code) has not told me the magic goo; I have not seen any
> posts from him so he may still be on Holidays.
> But I will delve into udev syntax to see what I need to change the mac addr.

I know with Arduinos (at least earlier network shields), there was no 
MAC address assigned, either. So there, I had to assign it in the 
compiled sketch.

I would expect there to be some program somewhere for the NIC to allow 
you to program the static MAC.

I suppose 'ifconfig -a' doesn't show anything?

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