ActiveXperts Network Monitor 2019 proactively manages network servers, devices, databases and more.

Microsoft Resource Kits - Windows 2003 Resource Kit

Qtcp.exe  (Windows 2003 Resource Kit)

The Window Server 2003 Resource Kit is a set of tools that system administrators and engineers use to manage or support a Windows Server 2003 system. Use it to streamline management tasks such as troubleshooting operating system issues, managing Active Directory, configuring networking and security features, and automating application deployment.
Qtcp.exe
This command-line tool measures end-to-end network service quality. Qtcp sends a sequence of test packets through a network, then reports on the queuing delay experienced by each packet. Packets that do not arrive at the destination are recorded as dropped packets. This tool can be used on either a production network or a controlled test network.