Introduction
The internet is a vast network connecting millions of devices worldwide. For these devices to communicate with each other, they need unique addresses, just like houses need unique addresses to receive mail. This unique address is called an IP (Internet Protocol) address. In this article, we will take a deep dive into IPv4 addresses, exploring their history, classes, and different types.
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The History of IPv4
IPv4, or Internet Protocol version 4, is the fourth version of the Internet Protocol. It was developed in the early 1980s and is still the most widely used version today. When the internet was in its infancy, engineers needed a way for computers to communicate with each other. They created IPv4, which uses a 32-bit address system, meaning it can support around 4.3 billion unique addresses.
What Does an IPv4 Address Look Like?
An IPv4 address is a series of four numbers separated by periods (.). Each number can range from 0 to 255. For example: 192.168.1.1
This structure is known as "dotted-decimal" notation. Each number in the series is called an "octet" because it is made up of eight bits.
IPv4 Address Classes
IPv4 addresses are divided into different classes. These classes help organize the addresses and make it easier to manage the internet. There are five main classes of IPv4 addresses: Class A, Class B, Class C, Class D, and Class E.
Class A Range: 1.0.0.0 to 126.0.0.0
Default Subnet Mask: 255.0.0.0
Usage: Class A addresses are designed for very large networks, such as those operated by large companies or governments.
Example: 10.0.0.1
Class B Range: 128.0.0.0 to 191.255.0.0
Default Subnet Mask: 255.255.0.0
Usage: Class B addresses are used by medium-sized networks, such as universities and large businesses.
Example: 172.16.0.1
Class C Range: 192.0.0.0 to 223.255.255.0
Default Subnet Mask: 255.255.255.0
Usage: Class C addresses are for smaller networks, like those in small businesses or home networks.
Example: 192.168.1.1
Class D Range: 224.0.0.0 to 239.255.255.255
Usage: Class D addresses are used for multicast groups. Multicast allows a single data stream to be sent to multiple destinations simultaneously.
Example: 224.0.0.1
Class E Range: 240.0.0.0 to 255.255.255.255
Usage: Class E addresses are reserved for experimental purposes. They are not used in standard operations.
Example: 240.0.0.1
Public and Private IP Addresses
IPv4 addresses can be either public or private. Understanding the difference is important for knowing how devices connect to the internet and communicate within local networks.
Public IP Addresses
Public IP addresses are used on the internet and must be unique across the entire internet. They are assigned by the Internet Assigned Numbers Authority (IANA) and distributed by regional organizations. Public IP addresses allow devices to communicate across different networks and access the internet.Example: 8.8.8.8 (Google's public DNS server)
Private IP Addresses
Private IP addresses are used within local networks, like those in homes, schools, or offices. They are not unique across the entire internet but must be unique within their local network. Devices with private IP addresses can communicate with each other within the same network but need a public IP address (usually provided by a router) to access the internet.
There are specific ranges of IP addresses reserved for private use. These ranges are:
Class A Private Range: 10.0.0.0 to 10.255.255.255
Class B Private Range: 172.16.0.0 to 172.31.255.255
Class C Private Range: 192.168.0.0 to 192.168.255.255
Why Use Private IP Addresses?
Using private IP addresses helps conserve the number of public IP addresses needed. Since private addresses are only used within local networks, many networks can use the same private IP address ranges without conflict. This system also adds a layer of security because private IP addresses are not directly accessible from the internet.
How IP Addresses are Assigned
When you connect to the internet, your device needs an IP address. This address can be assigned in two ways:
Static IP Address: This address is manually assigned and does not change. It’s like having a permanent home address.
Dynamic IP Address: This address is assigned by a DHCP (Dynamic Host Configuration Protocol) server and can change each time you connect to the network. It’s like staying at different hotels, where you get a new room number each time.
Most home networks use dynamic IP addresses because it’s easier to manage and ensures that devices get an IP address automatically when they connect.