ARP Poisoning (Address Resolution Protocol Poisoning) is an attack where the attacker associates their MAC address with the IP address of another machine, potentially leading to network disruption or interception of data.

DNS (Domain Name System) is responsible for translating human-readable domain names, like www.example.com, into IP addresses that computers use to identify each other on a network. DNS acts as the internet's "phonebook."

The most suitable tool for checking the IP address associated with a domain name is "nslookup." This command-line tool is used to query DNS (Domain Name System) servers to obtain information about domain names, including their corresponding IP addresses. It's a valuable tool for troubleshooting network connectivity issues.

The Application, Presentation, and Session layers of the OSI model correspond to the Application layer in the TCP/IP model. The Application layer in the TCP/IP model is responsible for providing network services directly to applications. It serves as the interface between software applications and the network stack, handling tasks such as data encryption and decryption, data compression, and application-level protocols.

Fiber Optic Cable is considered the most robust transmission medium. It uses glass or plastic fibers to transmit data as pulses of light, making it immune to electromagnetic interference and highly durable, making it suitable for harsh environments.

A CIDR notation of /16 in an IPv4 address means that the first 16 bits are used for the network prefix. This notation is used to represent the subnet mask and the network prefix in IPv4 addresses.

When devices on the network send data to an unexpected MAC address while the IP address is correct, it could be indicative of ARP (Address Resolution Protocol) Spoofing. ARP Spoofing is a type of attack where an attacker associates their MAC address with another device's IP address, redirecting traffic meant for that IP address to the attacker's system. This can lead to a security breach. DNS Hijacking, IP Spoofing, and Packet Fragmentation are different issues with distinct characteristics.

In an Ethernet network, the MAC address is typically 48 bits (6 bytes) in length. It is usually represented as a series of 12 hexadecimal characters, separated by colons or hyphens.

A PAN (Personal Area Network) typically covers a smaller area, focusing on individual or immediate vicinity connections, such as connecting a smartphone to a laptop via Bluetooth. In contrast, a LAN (Local Area Network) serves a more extensive area, typically within a building or campus, connecting devices for personal and business use.

In a Star Topology, if one node fails, it does not affect the rest of the network. Each device is directly connected to a central hub or switch, so the failure of one device does not impact the others.