Communications infrastructures are a critical asset in today’s information society. However, legacy telecommunication systems easily collapse in case of disruptions that may occur due to security incidents or crises. In this chapter, we first elaborate on the major shortcomings of the current communications networks for security applications to identify the key missing requirements for such networks. Then, we show that the ad hoc networking technologies, coupled with disruptive-tolerant techniques, are the best suited paradigm to build the next generation of dependable, secure, and rapidly deployable communications infrastructures. In particular, we focus on mesh, opportunistic, vehicular, and sensor networks giving an overview of the most recent advances and summarizing the challenges facing the design and the deployment of these networks. Finally, we conclude this chapter presenting the open research issues to realize the vision of a dependable communications infrastructure, with special attention to aspects such as interoperability among multiple heterogeneous networks, autonomic network management, and QoS protection.