MANET Privacy - Massive amounts of data are being stored in cyberspace as a result of the expansion of the Internet, IoT, and various networking technologies. The privacy and security are the most essential aspects of a network. This survey analyzed the functions of blockchain in network security. The blockchain-based network security mechanism may be used to increase network security because of its decentralization, tamper-resistance, traceability, high availability, and credibility. This survey offers a review of network security studies and their contributions and limits with a critical comparison analysis based on a complete and comprehensive research of the evolution of Blockchain, architectures, working principle, security, and privacy features. This analysis examines network security applications based on blockchain technology with various networking technologies, such as IoT, Industrial IoT, WSN, MANET, VANET, Vehicular Social Network, In-vehicle networking, mobile networks (5G), and so on. For communication, the majority of these networking technologies were combined with IoT. As a result, in this study, the Internet of Things is considered as the primary network employed in important research as examined in the literature review. As a result, the application of network security utilizing blockchain was examined in this study using IoT. This research presents a comparison based on several network solutions that employ blockchain for network security. Finally, the blockchain application in various networks, as well as its difficulties, are examined.