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Internet of Things (IoT) Technologies
Published in Vivek Kale, Parallel Computing Architectures and APIs, 2019
The assignment of an IP address to an individual computer can be permanent or temporary. Typically, the computers providing server functions have permanent IP addresses. Also, ISPs assign IP addresses permanently to broadband modems. However, almost all client computers in an enterprise lack permanent IP addresses. Once a range of IP addresses is allocated to a subnet, the assignment of individual IP addresses to individual computers is usually performed dynamically via a Dynamic Host Control Protocol (DHCP) server. This eliminates the tedious task of assigning addresses manually to every client computer in the network. When a computer connected to the subnet is turned on, it communicates with a DHCP server requesting an IP address (along with the subnet mask and gateway address). The server, from the existing pool, determines an available IP address and assigns it to this computer. When the computer is turned off, the IP address is returned to the pool and may be assigned to some other computers. There is no guarantee that the same IP will be assigned to the same computer the following time.
Internet of Things (IoT) Computing
Published in Vivek Kale, Digital Transformation of Enterprise Architecture, 2019
The assignment of an IP address to an individual computer can be permanent or temporary. Typically, the computers providing server functions have permanent IP addresses. Also, ISPs assign IP addresses permanently to broadband modems. However, almost all client computers in an enterprise do not have permanent IP addresses. Once a range of IP addresses are allocated to subnet, the assignment of individual IP addresses to individual computers are usually performed dynamically via a server called Dynamic Host Control Protocol (DHCP) server. This eliminates the tedious task of assigning addresses manually to every client computer in the network. When a computer connected to the subnet is turned on, it communicates with a DHCP server requesting an IP address (along with the subnet mask and gateway address). The server, from the existing pool, determines an available IP address and assigns it to this computer. When the computer is turned off, the IP address is returned to the pool and may be assigned to some other computers. There is no guarantee that the same IP will be assigned next time to the same computer.
Network Threats
Published in Nicholas Kolokotronis, Stavros Shiaeles, Cyber-Security Threats, Actors, and Dynamic Mitigation, 2021
Panagiotis Radoglou Grammatikis, Panagiotis Sarigiannidis
The DHCP protocol is a client-server-based protocol, which undertakes to configure automatically the network parameters of new host introduced in a network. In particular, the parameters filled automatically by DHCP are (a) the IP address, (b) the subnet mask, (c) the default gateway, (d) the DNS server, and (e) the leased time. Although the presence of DHCP is critical and necessary, it is characterized by two main security issues. First, it does not include any authentication mechanism. Therefore, the DHCP clients cannot know whether the corresponding server is trusted or not and similarly, the DHCP clients cannot know if they can trust the DHCP server or not. Secondly, DHCP messages are transmitted in plaintext. The DHCP spoofing MiTM attack can be performed by inserting a rogue DHCP server, which should act faster than the legitimate one, by answering to the DHCP client. In particular, the following four-step communication should be performed for the successful DHCP spoofing MiTM attack. The DCHP client (i.e. the new host) broadcasts a DHCP Discovery message.The rogue DHCP server transmits a DHCP Offer message.The DHCP client broadcasts a DHCP Request message.Finally, the rogue DHCP server transmits a DHCP ACK.
Smart building energy management based on network occupancy sensing
Published in Journal of International Council on Electrical Engineering, 2018
Xianing Jin, Guanqun Wang, Yi Song, Chongbo Sun
DHCP can be used as a similar measure as ARP of the number of hosts on a network [4]. DHCP is used by non-permanent hosts to lease an IP address for a temporary period of time. A DHCP server has a pool of IP addresses and maintains a table of which addresses are currently leased-out. Thus, the DHCP lease data is a measure of the number of active hosts on the network not including the hosts with fixed IP addresses, typically servers). In wireless networks the majority of (if not all) hosts use DHCP to obtain an IP address. Additional measures related to DHCP include the number of new hosts, the number of hosts which hop between wireless access points (APs), and the number of hosts whose leases have expired. These DHCP measures may relate to occupancy measures of people entering the building, moving within the building, and leaving the building within the last DHCP timeout period.