Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I would like to be able to reboot a server which is prone to go into a "hard lock" (ie I am even unable to reset it with "magic sysrq", neither see anything on screen nor get nothing out of the logs afterwards).

I wondered about connecting a cord from another computers com port and "break the power" with a fancy command from shell. The big problem is: I know next to nothing about com ports and how they send out interference...

Does this product exist? Do anybody know of how to create one in the office?

share|improve this question
up vote 3 down vote accepted

There are a variety of RS-232 / serial controller power switches out there. I'll include links to a couple products below. They are not inexpensive, typically.

Some UPSs have switchable output groups and to allow you to power-cycle outlets on the UPS via its management interface. Be sure to look into that.

If your server computer has a "lights out" management interface (HP/Compaq iLO, Dell Remote Assisance Card) you can typically power-cycle the host system from that management interface as well.

Finally, here's a how-to "do it yourself" article, but I'd highly recommend against doing anything like this for a serious datacenter environment.

share|improve this answer
great answer, thanks. – blippe Aug 4 '09 at 14:45

If it's true server-grade hardware (not a re-purposed desktop) it will likely have built-in IPMI controls. For example, my Penguin Computing and Dell servers can all be rebooted or powered on/off remotely regardless of the state of the OS.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.