NIS+, or Network Information Service Plus, is a protocol used for managing network resources in a distributed computing environment. It provides a centralized way to store and retrieve information about users, groups, and other network services, making it easier for administrators to manage large networks. Originally developed by Sun Microsystems, NIS+ enhances the older NIS protocol by adding security features and improved data management capabilities. It allows for better access control and supports a hierarchical namespace, which helps in organizing network resources more efficiently.