NetScanTools is a collection of over 40 network utilities for Windows, designed with an easy user interface in mind. It includes DNS tools, a ping and port scanner, traceroute, and other utilities. It comes in bundles with more or fewer tools based on the price.
NetScanTools is really a collection of different pentesting tools that a system admin would find particularly useful. The range of network toolkits are designed for those who work in network engineering, network security, network administration, network training, or law enforcement internet crime investigation. Like many other pentesting tools, the developers offer a free and commerical grade of their products.