Internet Control Message Protocol (ICMP) Attack: An Internet Control Message Protocol (ICMP) attack, such as a ping flood, is a type of Denial-of-Service (DoS) or Distributed Denial-of-Service (DDoS) attack. It involves an attacker flooding a target's network with ICMP echo request packets, commonly known as "pings," to overwhelm and incapacitate the network, causing legitimate requests to be denied service. This can lead to disruptions in both network connectivity and service availability.

Internet Corporation for Assigned Names and Numbers (ICANN): A non-profit organization responsible for coordinating the maintenance and procedures of several databases related to the namespaces and numerical spaces of the Internet. These responsibilities include IP address space allocation, protocol identifier assignment, generic (gTLD) and country code (ccTLD), Top-Level Domain name system management, and root server system management. ICANN's role ensures the network's stable and secure operation.

Internet Engineering Task Force (IETF): An open standards organization that develops and promotes voluntary Internet standards. It focuses on the technical and practical aspects of Internet technologies, conducting its work through numerous working groups organized by topic area (such as routing, transport, and security). Each group works to develop standards for its specific area, following a well-defined process that includes extensive peer review.

Internet Group Management Protocol (IGMP): A communications protocol used by hosts and adjacent routers to establish multicast group memberships. It is an integral part of IP multicast and allows a host to advertise its multicast group membership to any neighboring multicast routers. IGMP ensures efficient use of resources when supporting these types of multicast applications, as network devices can filter out irrelevant multicast traffic and better control the flow of relevant multicast traffic.

Internet Layer: The Internet Layer is a concept from the TCP/IP model that correlates to the OSI model's Network Layer. It is responsible for packet forwarding, including routing through intermediate routers, and it defines protocols to achieve scalable and fault-tolerant routing across the complex inter-networks of the global Internet.

Internet Message Access Protocol (IMAP): A protocol used for accessing and managing email messages on a remote server. It is commonly used in email clients to allow users to access their email from multiple devices. Examples of IMAP in use include users checking their email on their phone and laptop or a user organizing their email messages into folders.