IBM BMC Two MAC addresses detected from onboard Ethernet

BMC에서 두개의 MAC이 올라올때 조치 방법입니다.

Source

RETAIN tip: H191088

Symptom

The IBM server is connected to a network switch using the on-board Ethernet port 1. In certain network switch configurations, the switch detects the MAC address of the Baseboard Management Controller (BMC) when the IBM server is powered on and booting up such as during POST. Sometimes, particularly if the switch is configured to allow only one MAC address (e.g. port security), the switch may lock onto the BMC MAC address. This will prevent the operating system from utilizing the onboard ethernet port 1. The operating system may report that the network port or device is unavailable. This can occur if the BMC ethernet network configuration within F1 BIOS is set to either a static IP or DHCP.

Note: This issue only applies to BMC-equipped IBM xSeries and System x servers.

Affected configurations

This tip is not hardware specific.
This tip is not option specific.
This tip is not software specific.

Workaround

If possible, examine the network switch configuration to see if port security or other MAC-isolation features can be disabled, or if the network switch can be configured to accept and recognize two MAC addresses.

If this is not possible, then disable IPMI on the onboard Broadcom chipset. This will disable remote BMC access through the shared onboard ethernet port 1. Only the operating system will be able to use this port.

To disable IPMI, boot to the Broadcom Firmware Update Utility CD v1.20.26 or higher and run the following command:

• update model-type noipmi (example: update 8863 noipmi)

To re-enable IPMI, simply type the command without the "noipmi" parameter:

• update mode-type
  

Additional information

By default, the IBM server will share the onboard ethernet port 1 between the operating system and the BMC, each having its own MAC address and IP address. This allows remote access to the BMC through this single ethernet connection while the operating system is running as well as when the server is powered off. AC power must be applied to be able to access the BMC through the ethernet port.

However, in certain network switch configurations, the switch allows only one MAC address to utilize that specific network port. When the IBM server is powered-on and performing its POST/initialization functions, the network switch may detect the BMC MAC and lock its switch port to accept only packets coming from this MAC address.

Disabling IPMI will keep the BMC from sharing the onboard ethernet port 1 with the operating system, but you will no longer be able to access the BMC remotely via ethernet connection. Access to the BMC is possible, however, through operating system device drivers (OSA IPMI) and applications such as Dynamic System Analysis (DSA) or IBM Director.

If an Remote Supervisor Adapter (RSA) adapter/controller is installed, you can still access hardware event information using the RSA ethernet connection/port. Disabling IPMI on the onboard Broadcom ethernet has no affect on the RSA.

Reflashing the onboard Broadcom firmware will automatically reset IPMI to enabled unless the "noipmi" parameter is used.