Ambient energy-harvesting technology is a promising approach to keep wireless sensor networks (WSNs) operating perpetually. Depending on the harvesting source nodes can either be active (alive) or inactive (dead) at any instant in such Energy-Harvesting WSNs (EH-WSNs). Thus, even in a static deployment of EH-WSNs, the network topology is no longer static. A popular method to increase energy-efficiency in WSNs is by employing topology control algorithms. Most of the topology control algorithms in the literature cannot handle the situation when nodes have different energy-levels, and when number of active nodes varies with time in EH-WSN. To address this issue, we present two localized energy based topology control algorithms, viz., EBTC-1 and EBTC-2. EBTC-1 is for convergecast applications of WSNs and EBTC-2 is for a generic scenario where all nodes are required to be connected. While typical topology control algorithms select a particular number of neighbors, the distinguishing feature of both these algorithms is that they select neighbors based on energy-levels, and render the global topology strongly-connected. Simulation results confirm that EBTC-1 and EBTC-2 reduce the transmission power and they let nodes have neighbors with high remaining energy. Results show that our proposed algorithms increase at least 33% in the remaining energy per neighbor. In addition, in terms of energy consumption and fault-tolerance, our proposed algorithms typically achieve 1-connected topology using 74% less energy compared to K-Neigh.

DNSSEC offers protection against spoofing of DNS data by providing origin authentication, ensuring data integrity and authentication of non-existence by using public-key cryptography. Although the relevance of securing a technology as crucial to the Internet as DNS is obvious, the DNSSEC implementation increases the complexity of the deployed DNS infrastructure, which may result in misconfiguration. In this article, we measure and analyze the misconfigurations for domains in six zones (.bg, .br, .co, .com, .nl and .se). Furthermore, we categorize these misconfigurations and provide an explanation for their possible causes. Finally, we evaluate the effects of misconfigurations on the reachability of a zone’s network. Our results show that, although progress has been made in the implementation of DNSSEC, over 4 % of evaluated domains show misconfigurations. The domains with the most frequently appearing misconfiguration are often hosted at a very limited set of hosting providers. Of these misconfigured domains, almost 75 % were unreachable from a DNSSEC-aware resolver. This illustrates that although the authorities of a domain may think their DNS is secured, it is in fact not. Worse still, misconfigured domains are at risk of being unreachable from the clients who care about and implement DNSSEC verification, while the publisher may remain unaware of the error and its consequences.

DNSSEC offers protection against spoofing of DNS data by providing authentication of its origin, ensuring integrity and giving a way to authenticate denial of existence by using public-key cryptography. Where the relevance of securing a technology as crucial to the Internet as DNS is obvious, the DNSSEC implementation increases the complexity of the deployed DNS infrastructure, which may manifest in misconfiguration. A misconfiguration not only leads to silently losing the expected security, but might result in Internet users being unable to access the network, creating an undesired unreachability problem. In this paper, we measure and analyze the misconfigurations for domains in four zones (.bg, .br, .co and .se). Furthermore, we classify these misconfigurations into several categories and provide an explanation for their possible causes. Finally, we evaluate the effects of misconfigurations on the reachability of a zone's network. Our results show that, although progress has been made in the implementation of DNSSEC, over 4% of evaluated domains show misconfigurations. Of these misconfigured domains, almost 75% were unreachable from a DNSSEC aware resolver. This illustrates that although the authorities of a domain may think their DNS is secured, it is in fact not. Worse still, misconfigured domains are at risk of being unreachable from the clients who care about and implement DNSSEC verification while the publisher may remain unaware of the error and its consequences.