The US National Institute of Standards and Technology (NIST) and its National Cybersecurity Center of Excellence (NCCoE) issue the final version of NIST Cybersecurity Practice Guide Special Publication 1800-15, Securing Small-Business and Home Internet of Things (IoT) Devices: Mitigating Network-Based Attacks Using Manufacturer Usage Description (MUD). This guide explains how MUD protocols and tools can reduce: (1) the vulnerability of IoT devices to network-based threats and (2) the potential for harm from exploited IoT devices. The guide also explains IoT device developers and manufacturers, network equipment developers and manufacturers, and service providers who employ MUD-capable components to integrate and use MUD to ensure IoT users' security requirements.