Remotely turning on computer?

I need a simple way to turn on my dell optiplex remotely, and shut it off. Its running ubuntu 13.04. How would i go about that? would i need a separate device to press the power button, or would it be as simple as installing a card to the machine?

If I understood correctly you are looking for "Wake on LAN", which is supported by DELL Optiplex systems (at least in principle).

1. Enable "Wake on LAN" in the BIOS of the target.
2. Disable "Deep Sleep" in the BIOS of the target.
3. On your "other" Computer (assuming it is in the same LAN) install wakeonlan . This tool can send "magic packets" to the target.
4. Now create a file (lets call it optiplex.wol) in your home directory with just MAC address of the Optiplex (like 54:04:a6:a0:90:a1) as content.
5. Type wakeonlan -f optiplex.wol - the machine should start within seconds

Try Remotewakeup. It allows you to start your computer over the internet.

For complete instructions visit their site

If the system is switched off, make sure power is still getting to the network card. Make sure that the LAN connector light is on.

It's possible that this question is relevant : How can I enable wake-on-lan permanently?

I'd add that I'm not aware of any way to remotely shutdown the computer, short of SSH'ing to the device and issuing a halt or shutdown now command.

An added idea may be to research APC managed power bars. These network-based devices provide various power ports, each of which can be turned on/off by visiting the device's web page. The PC would have to set to power on when power is restored though and not all PC's support that setting in their BIOS.