It sounds very much like it could be a system similar to HP's iLO. I don't know any details, but it seems this is another computer in the server which is always running as long as the server is connected to the mains. It has another network card and IP address and you can connect to it with a web browser and turn the power supply on/off, provide boot media over the network/internet, and use it a bit like VNC, remote screen keyboard and mouse for installing an operating system remotely. Some of these features are paid for extras where you have to enter a serial number to use them on your own server!
Something like this obviously has to have pretty good access to the main computer. Even if the Dell computer 'code on flash on the motherboard which we're not going to call firmware' isn't anything like iLO, this is another place for firmware based viruses to hide.