My takeaways: >"Out-of-band management, sometimes also called lights-out management, identifies a capability that is almost unheard of in clients. A separate,

My takeaways: >"Out-of-band management, sometimes also called lights-out management, identifies a capability that is almost unheard of in clients. A separate, smaller management computer allows for remote access to a server even when it is, say, powered off. The terms out-of-band and in-band in this context emerge from their customery uses in networking and telecom, meaning that out of band management is performed without the use of the standard (we might say "data plane") network connection to a machine. But in practice they have drifted in meaning, and it is probably better to think of out-of-band management as meaning that the operating system and general-purpose components are not required. This might be made clearer by comparison: a very standard example of in-band management would be SSH, a service provided by the software on a computer that allows you to interact with it. Out-of-band management, by contrast, is provided by a dedicated hardware and software stack and does not require the operating system or, traditionally, even the CPU to cooperate." [...] >"The IPMI software runs on a processor conventionally called the baseboard management controller or BMC, and the terms IPMI and BMC are sometimes used interchangeably. Lights-out management or LOM is mostly an obsolete term but sticks around because HP(E) is a fan of it and continues to call their IPMI implementation Integrated Lights-Out. The BMC should not be confused with the System Management Controller or SMC" [...] "IPMI offers "sideband" networking. With sideband management, the BMC communicates directly with the same NIC that the operating system uses. The implementation is a little bit weird: the NIC will pretend to be two different interfaces, mixing IPMI traffic into the same packet stream as host traffic but using a different MAC address." [...] "Details of network features vary between IPMI implementations, but there is a standard interface on UDP 623 that can be used for discovery and basic commands. There's often SSH and a web interface, and VNC is pretty common for remote console." This is arguably the best educational article on IPMI and related subsystems (I did not know about 90% of this!) that I've read for a long time. Well worth a re-read in the future...