Microsoft Knowledge Base article 837243 begins with:
This article discusses the Port Reporter tool. The Port Reporter tool runs as a service on computers that are running Windows Server 2003, Windows XP, and Windows 2000. The tool logs TCP and UDP port activity. This article contains information about how to obtain and install the tool. When you install the tool, the Setup program creates the appropriate registry entries and installs the Port Reporter service.
This article also contains information about how to use start parameters to configure the Port Reporter service and information about the Port Reporter log files that are generated by the Port Reporter service.