I understand you don't want to install a special server on all machines? If so, your best choice (IMO) is a port scan (probably not a full one, just ports you may find important (mail: pop3 and smtp, ftp, www and so on). When you have info if the port if open or closed you may guess what's the machine. You need to use ping, too. Using ping you can check if machine is up or not. What I can think about is that it would be great if you can have access to routing table of the machine you run the scan from.
Last edited by Mara; 07-15-2003 at 04:02 PM.