WakeOnLAn

[Alexander Dupuy]

madunix wrote:

> > I want to turn on/off DELL PE 28xx 29xx Servers remotely (WOL) running
> > CentOS and RHEL, the servers are allocated of different locations

I don't know about the 28xx, but the BMC which is standard on at least
some of the 29xx (2950 for sure, but probably others too) provides a
much better mechanism for power control of remote servers - IPMI over LAN.

You write about "different locations" - one of the difficulties of
Wake-on-LAN is that you have to be on the local network for it to work
(sending it through a router won't be able to find a MAC address for the
IP and it won't be transmitted on the remote LAN).  So you have to have
a WoL "server" or proxy on each LAN to send the WoL packets.

The IPMI over LAN interface on the BMC allows you to assign a separate
IP address (meaning that you can use IPMI through a router) for the BMC,
which remains on as long as the system is plugged into AC power, and you
can use this not only to power-on a system, but also power-cycle a stuck
system, set up a serial console (serial-over-lan) connection so that you
can tweak the BIOS, boot off of alternate devices, etc. etc.  This is
*vastly* more useful than the simply "turn on another machine on the
local network" that Wake-on-LAN gives you.

You can enable the IPMI-over-LAN support on the BMC, and set a password,
from the BIOS (Ctrl-E on the PE 2950 to configure "Remote Management")
and use the ipmitool command on other systems to send the different
chassis commands for power on/off/reset.

@alex

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