Query for computers on a domain that are online

If you watch the outbound traffic from DameWare, it just snags all the computer objects from AD and then tries to connect to them via their hostname using NETBIOS.

Thats extremely simple to re-create, no magic involved.

Active directory users and computers will provide you a list of all machine accounts in the domain. Other than in scripts, I've never had to worry about whether a machine is online of offline because the changes I make are done via group policy. For desktop support, if I can't walk the user through telling me his machine name, i've got far bigger problems than how to connect.