Future Internet of Things is being deployed massively, since it is being already concerned deployments with thousands of nodes, which present a new dimension of capacities for monitoring solutions such as smart cities, home automation, and continuous healthcare. This new dimension is also presenting new challenges, in issues related with scalability, security and management, which require to be addressed in order to make feasible the Internet of Things-based solutions. This work presents a Trust Extension Protocol for Authentication in Networks Oriented to Management (TEPANOM). This protocol allows, on the one hand, the identity verification and authentication in the system, and on the other hand the bootstrapping, configuration and trust extension of the deployment and management domains to the new device. Thereby, TEPANOM defines a scalable network management solution for the Internet of Things, which addresses the security requirements, and allows an easy, and transparent support for the management, which are highly desirable and necessary features for the successful of the solutions based on the Internet of things. The proposed protocol has been instanced for the use case of a fire alarm management system, and successfully evaluated with the tools from the Automated Validation of Internet Security Protocols and Applications (AVISPA) framework.