Buzz word list part 6

Introduction (NAT)

NAT is a method used by routers to translate private (internal) IP addresses to public (external) IP addresses and vice versa. It is commonly used to allow multiple devices in a local network to share a single public IP address when accessing the internet.

How NAT Works (NAT)

When a device in a private network sends data to the internet, the router modifies the packet's source IP address to the router's own public IP address. When the response returns, the router translates the destination IP address back to the private address of the device that initiated the request.

Example of NAT:

• In a home network, multiple devices (laptops, smartphones) can access the internet using a single public IP address provided by the ISP. NAT ensures that the responses are routed back to the correct device within the local network.

Introduction (Network)

A network refers to a group of devices (such as computers, printers, servers, etc.) that are connected together to communicate and share resources like data, files, and internet access. Networks can be either physical (wired connections) or virtual (wireless, cloud-based).

Types of Networks:

• Local Area Network (LAN): A network limited to a small geographic area, such as an office or home.

• Wide Area Network (WAN): A network that spans a large geographic area, like the internet or a corporate network connecting multiple locations.

• Personal Area Network (PAN): A network of personal devices like smartphones, tablets, and laptops.

Example of a Network:

• In a company, employees might connect to a network to access shared files and printers, enabling communication within the organization.

Introduction (WAN)

A WAN is a telecommunications network that covers a large geographic area, often spanning cities, countries, or even continents. It is used to connect local networks (LANs) and allow for communication over long distances.

How WAN Works

WANs rely on various technologies like leased lines, satellite links, and the internet to connect multiple LANs. The most well-known example of a WAN is the internet, which connects billions of devices globally.

Example of WAN:

• A business with offices in different cities may use a WAN to connect their internal LANs, allowing employees to access centralized resources and communicate with each other.

Introduction (LAN)

A LAN is a network that connects devices within a limited area, such as a home, office, or school. It typically uses wired (Ethernet) or wireless (Wi-Fi) connections to link devices, allowing them to share resources such as files, printers, and internet access.

How LAN Works

LANs are usually confined to a single building or a group of buildings. Devices within a LAN can communicate with each other directly without the need for routers or external communication networks, although a router may be used to provide internet access.

Example of LAN:

• In a corporate office, computers and printers are all connected via a LAN, enabling users to share files and access network resources like a central file server.

Introduction (MAC Address)

A MAC address is a unique identifier assigned to the network interface card (NIC) of a device. It operates at the data link layer of the OSI model and is used to identify devices on a local network.

How MAC Address Works

MAC addresses are typically assigned by the manufacturer of the network device and are hard-coded into the hardware. When devices communicate over a network, they use MAC addresses to identify each other, especially on LANs. MAC addresses are represented as a 12-digit hexadecimal number.

Example of MAC Address:

• A network switch uses MAC addresses to forward data frames to the correct device within a LAN. Each device in the network will have a unique MAC address, such as 00:14:22:01:23:45.

Introduction (NIC)

A NIC (Network Interface Card) is a hardware component that allows a computer or device to connect to a network. It can be wired (Ethernet) or wireless (Wi-Fi) and has a unique MAC address.

How NIC Works

The NIC allows the device to communicate with other devices over a network by sending and receiving data packets. It acts as the physical interface between the device and the network medium (e.g., cable or Wi-Fi signal).

Example of NIC:

• A laptop has a built-in wireless NIC that allows it to connect to a Wi-Fi network, or it might use an Ethernet NIC to connect to a wired network.

Introduction (ICMP)

ICMP is a network protocol used for error reporting and diagnostics in IP networks. It helps to manage and control network traffic, providing feedback about issues such as unreachable destinations or network congestion.

How ICMP Works

ICMP is used by network devices (like routers and hosts) to send error messages indicating problems with packet delivery. Common ICMP messages include:

• Echo Request and Echo Reply (used by ping to check connectivity)

• Destination Unreachable (indicates that a destination is unreachable)

• Time Exceeded (used by traceroute to show routing paths)

Example of ICMP:

• When you run the ping command to check if a server is reachable, the response you receive is an ICMP Echo Reply, indicating whether the server is online and how long it takes to communicate.