IPMI allows you to monitor and manage a computer without regard to its operating system state. See also wikipedia's article.
To reboot your local computer via IPMI, issue
ipmitool power cycle
But this is fairly uninteresting because you could as well issue
Special about IPMI is that you can use it with a DRAC no matter what the operating system or power state of your computer is. See the next chapter for this.
IPMI over LAN
You can send IPMI commands (like power cycle) over the network to a DRAC (c)ard that will execute these commands. In this example we assume your DRAC's IP address is 192.168.0.20 and you want to reboot the server where the DRAC is built in.
- make sure you can access the IPMI port over the network. The port number is 623, the protocol is UDP. Some network components do not forward special ports, so here is how you can find out if your way is free:
$ sudo nmap -sU -p 623 192.168.0.20 root's password: Starting Nmap 4.00 ( http://www.insecure.org/nmap/ ) at 2009-03-20 11:13 CET Interesting ports on ls3047r.wdf.sap.corp (10.20.90.29): PORT STATE SERVICE 623/udp open|filtered unknown MAC Address: 00:1E:4F:44:05:E6 (Unknown)
In this example you find port 623 being open, but filtered for UDP access. This means, there is no blocking network component in your way.
- make sure your card is set up to accept IPMI requests over the network. To do this, reboot your server and enter the DRAC configuration utility by pressing CTRL_E when prompted. In the utility, select "IPMI over LAN" and set it to "On".
- use ipmitool to issue the reboot command over the network. You will have to replace root and calvin with a user/password combination that fits your settings.
ipmitool -H 192.168.0.20 -U root -P calvin chassis power cycle