How to retrieve the list of powered on workstations?

People in the office usually keep their workstations on during the night.

I'm planning to do a power save there so I want to make sure I'll be able to talk directly to the owner of the workstation if he leaves his machine on during the night every day. For that, I need to retrieve a list of all the workstations that are ON at a certain time, every day.

How do I do that?

From serverfault homemdelata

• Not much information given, depends on your setup for complexity.

  Easiest way to get a list would just be to fire up nmap as a scheduled task and see when IPs do and don't respond. Map those IPs to users and ask them.

  You could also do the matching in advance and script the pinging and auto-send your email to the user if you'd like. Without environment details, the most general solution is ping sweep and look up who has which IP.

  Zypher : I would say NMAP is overkill. you could just ping the workstation.

  Anonymous : ping won't do the trick if someone is mean enough to block icmp requests

  sparks : Zypher - "People in the office" so unless they are sharing a machine he is looking for more than one.

  homemdelata : It's a Windows 2003 network with AD and all workstations have Windows XP Professional on it. Is that enough as detials? Which other environment details do you need? Let me know so I can edit the question to make it more complete.
  From sparks

• For windows workstations the "net view" command may work for you.

  From Chris Nava

• Do you use DHCP? You could use a short lease time (2 hours) and check the DHCP server table for renewals that occur in the 'verboten' hours.

  From pbrooks100

• In my environment i would do it 1 of 2 ways.

  1. I am a Spiceworks user, so it is pretty easy to monitor and report things like boot time, when systems were/are offline, restarts and etc. Then set up a report to run every morning for offenders (ie. last boottime not between 6-9am). It may be overkill to set up a separate server, yadda yadda yadda. If you want to give it a shot, it is free at http://www.spiceworks.com/

  2. I also have a Splunk syslog server set up, and have many of my systems in the office set to send event logs to this server. With a little AD group policy you start sending shutdown and boot events to the event logs. Then set up a script to monitor who is not shutting there systems off every night.

  I don't know if either one of these would help you at all, or work in your environment, it is just how I do it.

  From Skaughty