Current network management systems rely heavily on forms in their user interfaces. The interfaces reflect the intricacies of the network hardware components but provide little support for guiding users through tasks. There is a scarcity of useful graphical visualizations and decision-support tools. We applied a task-oriented approach to design and implemented the user interface for a prototype network configuration management system. Our user interface provides multiple overviews of the network (with potentially thousands of nodes) and the relevant configuration tasks (queries and updates). We propose a unified interface for exploration, querying, data entry and verification. Compact color-coded treemaps with dynamic queries allowing user- controlled filtering and animation of the data display proved well-suited for representing the multiple containment hierarchies in networks. Our Tree-browser applied the conventional node-link visualization of trees to show hardware containment hierarchies. Improvements to conventional scrollbar-browsers included tightly coupled overviews and detailed views. This visual interface, implemented with Galaxy and the University of Maryland Widget Library TM, has received enthusiastic feedback from the network management community. This application-specific paper has design paradigms that should be useful to designers of varied systems.