[CentOS] C7: NM and changing MAC addresses

Mon Oct 11 16:11:35 UTC 2021
Markus Falb <wnefal at gmail.com>

> On 11.10.2021, at 17:22, Simon Matter <simon.matter at invoca.ch> wrote:
> Hi,
>> On Mon, 11 Oct 2021, José María Terry Jiménez wrote:
>>> El 11/10/21 a las 13:00, Tom Yates escribió:
>>>> On Mon, 11 Oct 2021, José María Terry Jiménez 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