Missing workstation alarm through Network

[pvouzis]

We recently had a workstation stolen from our lab, and apart from replacing it we want to take some precautions.

What we are thinking is to put a cron job to run every few minutes (5, 10 or 15 min) to check if all the other workstations are still online. This way if somebody disconnects a workstation from the network for any reason (among others trying to steal it), it will be detected in a few minutes at least. When this happens we would like to have an email sent to the members of the lab. I know that it will not deter the thieves, but combined with the logs from the door card reader we will be able to narrow down the people that were in the room at a certain time window.

So, apart from any other ideas that could be used for security/alarm purposes, does anybody know if I can find a script that implements this idea?

Thanks.

[GNU-Fan]

You can use the ping command with a count of 1 and a reasonable short timetolive limit. If you receive the "Time to live exceeded" line, the alarm can be triggered.