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IP addressing

What is an IP address?

• An IP (Internet Protocol) address is a unique identifier given to devices which communicate over the Internet (WAN)

• IP addresses are dynamic, they can change

• IP addresses make it possible to deliver data to the right device

• A device connecting to a network will be given an IP address, if it moves to a different network then the IP address will change

IPv4

• Internet Protocol version 4 is represented as 4 blocks of denary numbers between 0 and 255, separated by full stops

• Each block is one byte (8 bits), each address is 4 bytes (32 bits)

• IPv4 provides over 4 billion unique addresses (2³²), however, with over 7 billion people and countless devices per person, a solution was needed

IPv6

• Internet Protocol version 6 is represented as 8 blocks of 4 hexadecimal digits, separated by colons

• Each block is 2 bytes (16 bits), each address is 16 bytes (128 bits)

• IPv6 could provide over one billion unique addresses for every person on the planet (2¹²⁸)

Subnetting

• Subnetting is the process of dividing a larger network into smaller, more manageable parts, called subnets (short for sub-networks)

• Each subnet works like a mini-network within the main network, allowing devices to communicate more efficiently

• Benefits of subnetting include:

  • Reduces network traffic – less data is broadcast across the whole network

  • Improves speed and performance – data stays within its local subnet

  • Increases security – limits access so not all devices can reach all parts of the network

  • Easier to manage and maintain – changes can be made to one subnet without affecting the rest

  • Improves organisation – helps group devices by department or function

• It’s commonly used in larger networks, like schools or businesses, to reduce traffic, keep data local, and make management easier

Public vs private IP addresses

• Public IP addresses are assigned to devices that need a constant connection to the internet

• Examples:

  • Web servers

  • Email servers

• Globally unique – no two devices can have the same public IP

• Allows devices to be directly accessed from anywhere on the internet

• Private IP addresses are assigned to devices on a Local Area Network (LAN) by a router

• Not routable on the internet – improves network security

• Used for items in a home or office, such as:

  • Laptops

  • Phones

  • Printers

• Allows internal communication without exposing devices to the public internet

Static vs dynamic IP addresses

• Static IP addresses are fixed IP addresses that do not change

• Assigned to devices that need a consistent address

  Commonly used for:

  • Websites

  • Remote access services

  • Email or file servers

• No management required once set

• Allows reliable access from anywhere on the network or internet

• Dynamic IP addresses are temporarily assigned when a device connects to the network

• Comes from a pool of available IP addresses

• Managed automatically by a DHCP server (Dynamic Host Configuration Protocol)

• Ideal for devices where a fixed address isn’t needed

  • e.g. laptops, smartphones, or guest devices