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Old 10-13-2010, 04:28 PM
Boris Epstein
 
Default the wandering MAC?

Hi all,

I have what appears to be a truly puzzling problem. I've got this P4
32-bit machine running CentOS 5.5 with XEN that has two NICs: one
onboard, an Intel Corporation 82540EM Gigabit and one on an expansion
card, Realtek Semiconductor Co., Ltd. RTL-8169 Gigabit. The second one
is recognized as eth1.

What's happening is, it is showing up under one of the two MAC's:
either 00:0a:cd:1a:c1:71 or 00:00:00:00:c1:71. If you reboot it the
MAC stays the same; if you shutdown and do a full powerdown it seems
to change.

Obviously, after it goes from one MAC to another you have to play with
the start-up scripts for this interface to start up correctly and this
becomes a major annoyance.

Any idea what all of this mess could mean?

Thanks.

Boris.
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Old 10-13-2010, 04:35 PM
Benjamin Franz
 
Default the wandering MAC?

On 10/13/2010 09:28 AM, Boris Epstein wrote:
> What's happening is, it is showing up under one of the two MAC's:
> either 00:0a:cd:1a:c1:71 or 00:00:00:00:c1:71. If you reboot it the
> MAC stays the same; if you shutdown and do a full powerdown it seems
> to change.
>
I would say the card is probably dying and replace it.

--
Benjamin Franz

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Old 10-13-2010, 04:37 PM
Boris Epstein
 
Default the wandering MAC?

On Wed, Oct 13, 2010 at 12:35 PM, Benjamin Franz <jfranz@freerun.com> wrote:
> On 10/13/2010 09:28 AM, Boris Epstein wrote:
>> What's happening is, it is showing up under one of the two MAC's:
>> either 00:0a:cd:1a:c1:71 or 00:00:00:00:c1:71. If you reboot it the
>> MAC stays the same; if you shutdown and do a full powerdown it seems
>> to change.
>>
> I would say the card is probably dying and replace it.
>
> --
> Benjamin Franz
>
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

Thanks.

That's possible, sure. I wonder though - it seems to work just fine
when it's up, pretty fast, no abnormal error rate, it is brand new.
But you could be right, of course.

Boris.
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Old 10-13-2010, 04:46 PM
Giles Coochey
 
Default the wandering MAC?

On 13/10/2010 18:37, Boris Epstein wrote:
> On Wed, Oct 13, 2010 at 12:35 PM, Benjamin Franz<jfranz@freerun.com> wrote:
>> On 10/13/2010 09:28 AM, Boris Epstein wrote:
>>> What's happening is, it is showing up under one of the two MAC's:
>>> either 00:0a:cd:1a:c1:71 or 00:00:00:00:c1:71. If you reboot it the
>>> MAC stays the same; if you shutdown and do a full powerdown it seems
>>> to change.
>>>
>> I would say the card is probably dying and replace it.
>>
> Thanks.
>
> That's possible, sure. I wonder though - it seems to work just fine
> when it's up, pretty fast, no abnormal error rate, it is brand new.
> But you could be right, of course.
>
I've tended to find that when a card is failing the MAC address starts
setting itself to FF:FF:FF:FF:FF:FF not 00:00:00:XX:XX:XX

The first three bytes are Vendor ID on a MAC address, you haven't got
anything in there that might fiddle with that? Is it an OEM card?
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Old 10-13-2010, 05:00 PM
Timo Schoeler
 
Default the wandering MAC?

On 10/13/2010 06:46 PM, Giles Coochey wrote:
> On 13/10/2010 18:37, Boris Epstein wrote:
>> On Wed, Oct 13, 2010 at 12:35 PM, Benjamin Franz<jfranz@freerun.com> wrote:
>>> On 10/13/2010 09:28 AM, Boris Epstein wrote:
>>>> What's happening is, it is showing up under one of the two MAC's:
>>>> either 00:0a:cd:1a:c1:71 or 00:00:00:00:c1:71. If you reboot it the
>>>> MAC stays the same; if you shutdown and do a full powerdown it seems
>>>> to change.
>>>>
>>> I would say the card is probably dying and replace it.
>>>
>> Thanks.
>>
>> That's possible, sure. I wonder though - it seems to work just fine
>> when it's up, pretty fast, no abnormal error rate, it is brand new.
>> But you could be right, of course.
>>
> I've tended to find that when a card is failing the MAC address starts
> setting itself to FF:FF:FF:FF:FF:FF not 00:00:00:XX:XX:XX

FF:FF:FF:FF:FF:FF is broadcast.

> The first three bytes are Vendor ID on a MAC address, you haven't got
> anything in there that might fiddle with that? Is it an OEM card?

Timo

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Old 10-13-2010, 05:06 PM
Giles Coochey
 
Default the wandering MAC?

On 13/10/2010 19:00, Timo Schoeler wrote:
> On 10/13/2010 06:46 PM, Giles Coochey wrote:
>>
>> I've tended to find that when a card is failing the MAC address starts
>> setting itself to FF:FF:FF:FF:FF:FF not 00:00:00:XX:XX:XX
> FF:FF:FF:FF:FF:FF is broadcast.
>
Sorry... in order to qualify my statement I should say that I was in
charge of United Kingdom RMAs for a Taiwanese manufacturer of Network
cards for 3 years... as such I have come across thousands of faulty
network cards and one of our tests for a faulty PROM was to ask our
distributors if the MAC addresses had set itself to FF:FF:FF:FF:FF:FF.

I don't doubt that it is a broadcast address.
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Old 10-13-2010, 06:45 PM
Boris Epstein
 
Default the wandering MAC?

On Wed, Oct 13, 2010 at 2:19 PM, Brunner, Brian T.
<BBrunner@gai-tronics.com> wrote:
>
>> I just tried a full powerdown with NTP deactivated. The
>> system came up, the time is fine.
>>
>> Not that the time on the motherboard should necessarily
>> affect the MAC on an expansion card, but that was a good test
>> nonetheless.
>
> I'm suspicious (as others have suggested) the card itself is bad. *I
> think to suspect the flash chip that stores the MAC addr. *The rest of
> the card may be perfect. *Using it long-term might require no more than
> a manual edit of the init script for it adding something to this effect
> 'if MAC == zeros; then set MAC to 00:0a:cd:1a:c1:71 fi'. *This will fix
> this card without clobbering it's successor down the road.
> ************************************************** *****************
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom
> they are addressed. If you have received this email in error please
> notify the system manager. This footnote also confirms that this
> email message has been swept for the presence of computer viruses.
> www.Hubbell.com - Hubbell Incorporated**
>
>

Brian,

While those suspicions were well justified I am not sure your guess is
correct in this particular case as I just swapped the NIC I had for a
different one and I seem to be getting the same sort of errors again.
What's the likelihood that two NICs in a row have a faulty flash?
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Old 10-13-2010, 06:55 PM
Eero Volotinen
 
Default the wandering MAC?

2010/10/13 Boris Epstein <borepstein@gmail.com>:
> On Wed, Oct 13, 2010 at 2:19 PM, Brunner, Brian T.
> <BBrunner@gai-tronics.com> wrote:
>>
>>> I just tried a full powerdown with NTP deactivated. The
>>> system came up, the time is fine.
>>>
>>> Not that the time on the motherboard should necessarily
>>> affect the MAC on an expansion card, but that was a good test
>>> nonetheless.
>>
>> I'm suspicious (as others have suggested) the card itself is bad. *I
>> think to suspect the flash chip that stores the MAC addr. *The rest of
>> the card may be perfect. *Using it long-term might require no more than
>> a manual edit of the init script for it adding something to this effect
>> 'if MAC == zeros; then set MAC to 00:0a:cd:1a:c1:71 fi'. *This will fix
>> this card without clobbering it's successor down the road.
>> ************************************************** *****************
>> This email and any files transmitted with it are confidential and
>> intended solely for the use of the individual or entity to whom
>> they are addressed. If you have received this email in error please
>> notify the system manager. This footnote also confirms that this
>> email message has been swept for the presence of computer viruses.
>> www.Hubbell.com - Hubbell Incorporated**
>>
>>
>
> Brian,
>
> While those suspicions were well justified I am not sure your guess is
> correct in this particular case as I just swapped the NIC I had for a
> different one and I seem to be getting the same sort of errors again.
> What's the likelihood that two NICs in a row have a faulty flash?

Well, you can set new mac address also manually on ifcfg-ethX script
.. or ifconfig ..

--
Eero
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Old 10-13-2010, 06:59 PM
Boris Epstein
 
Default the wandering MAC?

On Wed, Oct 13, 2010 at 2:55 PM, Eero Volotinen <eero.volotinen@iki.fi> wrote:
> 2010/10/13 Boris Epstein <borepstein@gmail.com>:
>> On Wed, Oct 13, 2010 at 2:19 PM, Brunner, Brian T.
>> <BBrunner@gai-tronics.com> wrote:
>>>
>>>> I just tried a full powerdown with NTP deactivated. The
>>>> system came up, the time is fine.
>>>>
>>>> Not that the time on the motherboard should necessarily
>>>> affect the MAC on an expansion card, but that was a good test
>>>> nonetheless.
>>>
>>> I'm suspicious (as others have suggested) the card itself is bad. *I
>>> think to suspect the flash chip that stores the MAC addr. *The rest of
>>> the card may be perfect. *Using it long-term might require no more than
>>> a manual edit of the init script for it adding something to this effect
>>> 'if MAC == zeros; then set MAC to 00:0a:cd:1a:c1:71 fi'. *This will fix
>>> this card without clobbering it's successor down the road.
>>> ************************************************** *****************
>>> This email and any files transmitted with it are confidential and
>>> intended solely for the use of the individual or entity to whom
>>> they are addressed. If you have received this email in error please
>>> notify the system manager. This footnote also confirms that this
>>> email message has been swept for the presence of computer viruses.
>>> www.Hubbell.com - Hubbell Incorporated**
>>>
>>>
>>
>> Brian,
>>
>> While those suspicions were well justified I am not sure your guess is
>> correct in this particular case as I just swapped the NIC I had for a
>> different one and I seem to be getting the same sort of errors again.
>> What's the likelihood that two NICs in a row have a faulty flash?
>
> Well, you can set *new mac address also manually on ifcfg-ethX script
> .. or ifconfig ..
>
> --
> Eero
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

OK... how do I set it? Or, more importantly, how do I find out what
MAC the card currently thinks it has?

Boris.
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Old 10-13-2010, 07:08 PM
Eero Volotinen
 
Default the wandering MAC?

2010/10/13 Boris Epstein <borepstein@gmail.com>:
> On Wed, Oct 13, 2010 at 2:55 PM, Eero Volotinen <eero.volotinen@iki.fi> wrote:
>> 2010/10/13 Boris Epstein <borepstein@gmail.com>:
>>> On Wed, Oct 13, 2010 at 2:19 PM, Brunner, Brian T.
>>> <BBrunner@gai-tronics.com> wrote:
>>>>
>>>>> I just tried a full powerdown with NTP deactivated. The
>>>>> system came up, the time is fine.
>>>>>
>>>>> Not that the time on the motherboard should necessarily
>>>>> affect the MAC on an expansion card, but that was a good test
>>>>> nonetheless.
>>>>
>>>> I'm suspicious (as others have suggested) the card itself is bad. *I
>>>> think to suspect the flash chip that stores the MAC addr. *The rest of
>>>> the card may be perfect. *Using it long-term might require no more than
>>>> a manual edit of the init script for it adding something to this effect
>>>> 'if MAC == zeros; then set MAC to 00:0a:cd:1a:c1:71 fi'. *This will fix
>>>> this card without clobbering it's successor down the road.
>>>> ************************************************** *****************
>>>> This email and any files transmitted with it are confidential and
>>>> intended solely for the use of the individual or entity to whom
>>>> they are addressed. If you have received this email in error please
>>>> notify the system manager. This footnote also confirms that this
>>>> email message has been swept for the presence of computer viruses.
>>>> www.Hubbell.com - Hubbell Incorporated**
>>>>
>>>>
>>>
>>> Brian,
>>>
>>> While those suspicions were well justified I am not sure your guess is
>>> correct in this particular case as I just swapped the NIC I had for a
>>> different one and I seem to be getting the same sort of errors again.
>>> What's the likelihood that two NICs in a row have a faulty flash?
>>
>> Well, you can set *new mac address also manually on ifcfg-ethX script
>> .. or ifconfig ..
>>
>> --
>> Eero
>> _______________________________________________
>> CentOS mailing list
>> CentOS@centos.org
>> http://lists.centos.org/mailman/listinfo/centos
>>
>
> OK... how do I set it? Or, more importantly, how do I find out what
> MAC the card currently thinks it has?

Well, ifconfig?

It really doesn't matter, just generate random one..

edit /etc/sysconfig/network-scripts/ifcfg-ethX

Remove HWADDR=00:00:00:00:00:00
add MACADDR=WH:AT:YO:UW:AN:T0

It should work this way and then just service network restart ..

--
Eero



--
Eero
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