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We are using a Supermicro X9DRi-LN4+/X9DR3-LN4+ motherboard with a dedicated IPMI port. We have a dedicated ethernet cable going into that port with a dedicated static IP address and everything works fine whilst the device is powered on. We can monitor the system components, remote into the device and power cycle...etc

However, once we shut down the device, either through Windows or IPMIView/Web, we can no longer connect to the device using the IPMI interface, we cannot even ping its own dedicated IPMI IP address any longer. IPMIView lists the device as "offline" and displays a message at the bottom left "Cannot communicate with device ".

Why would this be the case? IPMI (be it IPMIView or web interface) offers a "Power Off" and "Power On" feature so we assumed we should be able to power the device back on once it was shut down. We were also under the impression that IPMI works on a lower level so as long as there is power to the motherboard we should be able to connect to the device via IPMI and therefore be able to power it back on.

Can somebody please help us understand this?

many thanks!

n.l.
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A common reason communication to an IPMI device doesn't work when it is powered off is because the ethernet card is no longer advertising its MAC address (See Address Resolution Protocol or ARP if you are unfamiliar with this). So when a client tries to communicate to that IPMI device's ethernet port, the MAC address can't be determined, and no communication can occur. Given you have a static IP address configured, this is a likely reason for your issue.

There are several solutions to this that I can recall.

  • Newer IPMI devices can support ARP response when powered off, but it has to be enabled. In FreeIPMI's ipmi-config tool, this is the Lan_Conf_Misc:Enable_Arp_Response setting.

  • You can enable the IPMI device to send gratuitous ARPs, which basically are regular messages saying "IP address X.X.X.X is MAC address XX:XX:XX:XX:XX:XX", so that potential clients an cache this information. In FreeIPMI, this is the Lan_Conf_Misc:Enable_Gratuitous_Arps setting with the interval being set with Lan_Conf_Misc:Gratuitous_Arp_Interval

  • You can place the IP -> MAC address setting manually into your client's cache. I haven't done this in awhile, but I believe this is done with arp -s on Linux. I can't speak for other systems.

Albert Chu
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