CentOS - Oct 2021 - C7: NM and changing MAC addresses

Hi,
> On Mon, 11 Oct 2021, Jos? Mar?a Terry Jim?nez wrote:
>
>> El 11/10/21 a las 13:00, Tom Yates escribi?:
>>>  On Mon, 11 Oct 2021, Jos? Mar?a Terry Jim?nez wrote:
>>>
>>>>  Hello
>>>>
>>>>  Perhaps the solution is this:
>>>>
>>>>  https://access.redhat.com/solutions/70215HWADDR>>>
>>>  thanks, but either that link is broken, or the site requires a
login,
>>> as i
>>>  can't see anything and get redirected to a general search
page.? could
>>> i
>>>  trouble you to check the link?
>>>
>>>
>> Uh oh! Some copypaste at the end
>>
>> Is this one
>>
>> https://access.redhat.com/solutions/70215
>
> thank you very much for the suggestion!  sadly, this has not worked.
>
Are you even sure it's NetworkManager messing with your MAC addresses? I
have no idea why NM should ever mess with MAC addresses on a server and I
don't expect NM is doing so.

I have another idea: Seems this is on a SuperMicro server, can it be that
the box in question has a shared lights out management, sharing the
management ethernet port with the first LAN port? If so, can it be that
the management port is not configured properly and does try to DHCP an
IPv4 address? If you don't need the management stuff then you may try to
simply disable it to get rid of the mess.

Regards,
Simon

> On 11.10.2021, at 17:22, Simon Matter <simon.matter at invoca.ch>
wrote:
> 
> Hi,
> 
>> On Mon, 11 Oct 2021, Jos? Mar?a Terry Jim?nez wrote:
>> 
>>> El 11/10/21 a las 13:00, Tom Yates escribi?:
>>>> On Mon, 11 Oct 2021, Jos? Mar?a Terry Jim?nez wrote:
>>>> 
>>>>> Hello
>>>>> 
>>>>> Perhaps the solution is this:
>>>>> 
>>>>>
https://access.redhat.com/solutions/70215HWADDR>>>>
>>>> thanks, but either that link is broken, or the site requires a
login,
>>>> as i
>>>> can't see anything and get redirected to a general search
page.  could
>>>> i
>>>> trouble you to check the link?
>>>> 
>>>> 
>>> Uh oh! Some copypaste at the end
>>> 
>>> Is this one
>>> 
>>> https://access.redhat.com/solutions/70215
>> 
>> thank you very much for the suggestion!  sadly, this has not worked.
>> 
> 
> Are you even sure it's NetworkManager messing with your MAC addresses?
I
> have no idea why NM should ever mess with MAC addresses on a server and I
> don't expect NM is doing so.
> 
> I have another idea: Seems this is on a SuperMicro server, can it be that
> the box in question has a shared lights out management, sharing the
> management ethernet port with the first LAN port? If so, can it be that
> the management port is not configured properly and does try to DHCP an
> IPv4 address? If you don't need the management stuff then you may try
to
> simply disable it to get rid of the mess.
Yeah, there is a default setting in the Firmware of ?failover? which means
?use dedicated IPMI port if connected otherwise use shared LAN port?

This is under IPMI -> BMC Network Configuration
see also
https://serverfault.com/questions/361940/configuring-supermicro-ipmi-to-use-one-of-the-lan-interfaces-instead-of-the-ipmi

But, is this kind of traffic supposed to be visible to the linux kernel?
(or was the tcpdump made on another machine?)

Best Regards, Markus