CentOS - Apr 2012 - FOUND_THE_ISSUE -- URGENT -- pseudo network interface creating problem with dhcp-- centos 5.5

Hi John,

Thanks for the explanation.
I looked at the BIOS and found the following where the pseudo MAC
address is from:
################################################################################
Planar Ether 1 MAC Address: E4:1F:13:77:16:5F   ============> This is
shown in ifconfig eth0
Planar Ether 2 MAC Address: E4:1F:13:77:16:60   ============> This is
shown in ifconfig eth1

BMC MAC Address: E4:1F:13:77:16:61 ======> This is the MAC address my
SW is showing on the SW port connected to my eth0

Slot 1 MAC Address: 00:15:17:EB:AE:A4 ===========> This is shown in
ifconfig eth2
########################################################

I got some pointers over web on how to disable the BMC so that it
would not use eth0.
But another question in my mind is what is the significance of BMC MAC
address here? (How different is it from the MAC addresses of other
conneted NIC cards and how OS uses it)?
And why not BIOS shows all the NIC devices detected ? (because
"ifconfig -a" shows eth0/eth1/eth2/eth3 for me with eth3 MAC is:
00:15:17:EB:AE:A5. I could not see eth3 MAC address in the above BIOS
output).

Thanks for your time.

Regards,
Sri

On Thu, Apr 12, 2012 at 1:18 AM, John R Pierce <pierce at hogranch.com>
wrote:
> On 04/11/12 9:36 AM, sri wrote:
>> 4) Have you checked if your motherboard IPMI is not pulling an address
>> during boot?
>> -- Frankly, not sure how to check motherboard IPMI messages. Verified
>> dmesg output. Following is the dmesg output.
>> Please share any way to check motherboard IPMI is pulling another
address?
>
> well, first, does your motherboard *HAVE* an IPMI management module, and
> if so, does it use a ?dedicated ethernet port, or is it
'piggybacked' on
> eth0 ? ? the behavior shown could be the latter.
>
> I'd look in the system or motherboard documentation for this...
> depending on the IPMI module, it may have a web or ssh interface, or it
> may require another system contact it via an 'ipmitool' of some
sort.
> It probably has an initial user/pass like admin/admin which should be
> reconfigured during system configuration and deployment.
>
> --
> john r pierce ? ? ? ? ? ? ? ? ? ? ? ? ? ?N 37, W 122
> santa cruz ca ? ? ? ? ? ? ? ? ? ? ? ? mid-left coast
>
> _______________________________________________
> CentOS mailing list
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-- 
--
?Krishna Mohan B

On 04/13/12 1:14 AM, sri wrote:
> BMC MAC Address: E4:1F:13:77:16:61 ======>  This is the MAC address my
> SW is showing on the SW port connected to my eth0
>
The BMC ("Baseboard Management Controller" or something like that) is 
another name for a management processor, similar to the IPMI I 
mentioned.   This can be used for monitoring the system status, lights 
out management like remote power off and on (BMC is powered even when 
the server is shut down), etc.     I would recommend you learn how to 
use it and not disable it.   The BMC can also be used for remote system 
installation and such.

Have you consulted the hardware documentation on this system yet?
for instance, here's the BMC/IPMI software for various Dell servers
http://support.dell.com/support/edocs/software/smbmcmu/1.2/en/ug/bmcugc0d.htm

here's an overview of IPMI/BMC systems
http://en.wikipedia.org/wiki/Intelligent_Platform_Management_Interface


many servers have a hardware option to move the BMC/IPMI to a dedicated 
ethernet port, you'll need to consult with the system vendor to see if 
this option is available as a field upgrade for your server.


-- 
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast