Two tools no network administrator should be without:
  1. NMAP (www.insecure.org)
    Will perform network scans, and do a pretty good job of identifying the hardware. As seen in The Matrix
    It's a bit slower on Windows than Unix, but is still a superb tool. Will save you a lot of effort by identifying printers, routers, switches and so-on which you may not be interested in from a anti-virus perspective.
  2. Ethereal (www.ethereal.com)
    My favorite network packet sniffer. Use this interactively to spot "noisy" devices which are suspicious, or use the text mode "tethereal" in a script to gather active IP addresses. You will need a promiscuous port in a switched environment and it will only monitor traffic which passes through the local network so you will miss peer-to-peer traffic which is entirely in the WAN locale


If you are going the ping route, use a "parallel pinger" to avoid the lengthy run time of single streaming pings - search the board for an example of on of these.