http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnw2kmag01/html/NetworkTraffic.aspNetwork Monitor is an administrative tool that lets you monitor network traffic as it crosses the wire. Protocol parsers built in to the tool organize traffic into packets for ease of analysis and give you information you can use to track down problems with network applications, misconfigured workstations, and unnecessary protocols installed on workstations, printers, and servers. Network Monitor\'s features include display filters, which can help you locate specific information in large network traces; capture filters, which can narrow down the information the tool captures; and triggers, which let you tell your system to take a certain action based upon a packet\'s contents.
Network Monitor for Windows 2000 comes in two versions: a lite version, which ships with Win2K, and a full version, which is part of Systems Management Server (SMS) 2.0 and which you can also install on Windows NT 4.0. The lite version monitors only local traffic.