Modern servers come with a basement management controller (BMC), a little extra computer that allows remote console access, provides all kinds of hardware status information and even allows power control (i.e. turning the server on and off). Dell’s implementation is called iDRAC.

IPMI is a commonly used protocol to access this functionality, even over the network.

I remembered using ipmitool over the network to access the iDRAC in the past. The more I was surprised that suddenly it only gave me an error message:

$ ipmitool -H server-mgmt -U root mc info
Password:
Get Session Challenge command failed
Error: Unable to establish LAN session
Get Device ID command failed
Code language: plaintext (plaintext)

I found the solution in .pQd’s log:

Apparently recent firmware versions (in 2016) stopped supporting the default protocol and only continued to support the lanplus protocol, which can be selected with the -I lanplus option. I’m not sure, if I saw this documented somewhere, but it seems, that’s what Dell always intended to use. So the proper command is:

ipmitool -H server-mgmt -I lanplus -U root mc info
Code language: Bash (bash)

If you are using OpenIPMI, the proper option is –driver-type=LAN_2_0, so e.g. for reading sensor values you can use:

ipmi-sensors -h server-mgmt -u root -P --driver-type=LAN_2_0
Code language: Bash (bash)