What is IPv4?

IPv4, or Internet Protocol Version 4, is one of the core technologies that powers the modern internet. It defines how devices like computers, routers, and servers identify and communicate with each other using numerical addresses. IPv4 has been the backbone of online communication since the early 1980s and is still the most widely used addressing system today.

An IPv4 address is a 32-bit number that uniquely identifies a device on a network. Without IP addresses, devices would have no way of finding and sending data to one another across the internet.

IPv4 Address Format

IPv4 addresses are written in a form known as dotted decimal notation. Each address consists of four numbers separated by dots:

192.168.1.1

Each number ranges from 0 to 255, representing one byte (8 bits). The full IPv4 address contains 4 bytes for a total of 32 bits:

8 bits . 8 bits . 8 bits . 8 bits = 32 bits

This gives a total of approximately 4.3 billion possible addresses.

How IPv4 Works

IPv4 routes data across networks by breaking it into small units calledpackets. Each packet includes:

• Source IP address (sender)
• Destination IP address (receiver)
• Payload (the actual data)

Routers read the destination address and forward the packet along the best available path until it reaches its target device.

Public vs Private IPv4 Addresses

IPv4 addresses come in two major types:

Public IP Addresses

These are unique across the entire internet and assigned by ISPs. Examples:

8.8.8.8 (Google DNS)

Private IP Addresses

Used inside home or office networks and not routable on the internet. Common ranges include:

• 10.0.0.0 – 10.255.255.255
• 172.16.0.0 – 172.31.255.255
• 192.168.0.0 – 192.168.255.255

Your home WiFi network usually assigns private IPs like 192.168.1.x.

IPv4 Address Exhaustion

When IPv4 was created, 4.3 billion addresses seemed like more than enough. But with the growth of smartphones, laptops, IoT devices, and cloud systems, IPv4 addresses began running out.

To cope with this shortage, techniques like NAT (Network Address Translation) allow multiple devices to share a single public IP.

CIDR & Subnetting

Classless Inter-Domain Routing (CIDR) enables more efficient allocation of IP addresses. Instead of old class-based networks (A, B, C), CIDR uses a suffix like:

192.168.1.0/24

Here, /24 indicates how many bits belong to the network portion.

Subnetting helps network administrators divide larger networks into smaller segments for security, performance, and organization.

Common Uses of IPv4

IPv4 is used in almost every aspect of networking, including:

• Home internet connections
• Web servers & data centers
• Cloud platforms
• Mobile networks
• IoT devices
• Corporate networks

Challenges of IPv4

Although IPv4 has served the world for decades, it comes with limitations:

• Limited number of unique addresses
• No built-in security or encryption
• Cannot efficiently support the modern internet scale
• Relies heavily on NAT for multi-device homes

These limitations led to the development of IPv6, which offers a much larger address space.

IPv4 vs IPv6

Conclusion

IPv4 remains one of the most important core technologies of the internet. Its simple structure, reliability, and widespread support make it the foundation of online communication even decades after its creation. While IPv6 is slowly replacing it, IPv4 continues to play a critical role in networking, security, cloud computing, and everyday digital communication.

You can explore IPv4 ranges using our IPv4 Range Expander Tool.