IP Addressing Series – Part 2: IPv4 Explained in Detail

IPv4 (Internet Protocol Version 4) – Complete Beginner Friendly Guide

Understanding the Concept of IPv4

IPv4 (Internet Protocol Version 4) is one of the most important protocols used in computer networking. It is used to identify devices in a network and make communication possible between them. IPv4 performs a major role in networking.

We can say that IPv4 is a digital addressing system for all the devices that connected inside a network. If you are new to networking, then start by learning the basics of networking and its different types.

In today blog, we will understand the concept of IPv4, its structure and how IPv4 works. Before learning the advanced topics of cybersecurity, a basic understanding of IP addressing is very important for learners.

What is IPv4?

IPv4 stands for Internet Protocol Version 4 which is a connectionless protocol and used for communication. It routes data packets from source to destination and provides logical addresses to devices inside a network.

IPv4 is a 32 bit address because every IPv4 address has 32 binary bits, these bits divided into four sections.

IPv4 addresses written in a dotted decimal notation:

Example:

(192.168.16.25) the address is divided into four parts and each part separated by dot; additionally each section contains a decimal value that starts from 0 to 255.

This system makes IP addresses easy for humans to remember and read it.

Also, learn deeply about OSI model because IPv4 operates at the network layer of the OSI model.

Structure of IPv4

An IP address contains 32 bits and these bits divided into four parts. Each part contains 8 bits that why they called an octets.

Let’s take an example (192.168.16.25) this IP address divided into four parts means four octets.

• 1^st Octet (192)
• 2^nd Octet (168)
• 3^rd Octet (16)
• 4^th Octet (25)

Each octet contains 8 binary bits so the complete structure becomes:

8 bits + 8 bits + 8 bits + 8 bits = 32 bits

The combination of these octets creates a unique IP address; each octet has decimal value from 0 to 255 because 8 bits can create 256 possible combinations.

What is an Octet?

An octet is group of 8 bits. IPv4 address divided into four parts, each part contains 8 bits therefore each part is called an octet.

Computers do not understand decimal numbers; they only communicate in binary language, which only contains

• 0
• 1

Every IPv4 address is stored in binary format.

Let’s understand with an example:

The first octet (192) is in decimal, but when we convert it into binary. it contains exactly 8 digits (11000000).

In an IPv4 address:

(192.168.10.1) IPv4 address in decimal form

(11000000.10101000.00001010.00000001) IPv4 address in binary form

1 octet contains 8 bits therefore, Total octets = 4, Total bits = 32.

Humans prefer decimal notation, while networking devices and computer systems process IP addresses in binary format.

Working of IPv4

IPv4 plays a major role in network communication, The working process of IPv4 explained in several steps:

Step 1: A device receives an IPv4 address when it connects to a network. It may manually or automatically through DHCP.

This IP address is the address of device and also used to identify that device on a network.

Step 2: When user doing any activity such as sending a message, the device creates data packets, these packets contain information of data such as:

• Source IP address
• Destination IP address
• Data payload

Step 3: Firstly, router analyzes the destination IP inside data packet, then uses the routing table to find best path for forwarding the packets.

Step 4: The packets travel across multiple routers before reaching the best destination device.

Step 5: Finally the destination device processes the information after receiving the packets.

The entire process happens within few seconds over the internet.

Also, learn how packets move through different networking layers, check our guide on how data flows through networking layers.

Parts of an IPv4 Address

An IPv4 address is divided into two parts:

• Network ID
• Host ID

These parts are used to identify both network and specific device.

• The Network ID is used to identify the network to which a device belongs to.
• The Host ID is used to identify a specific device inside a network.

If you want to learn more about the Parts of IP address, read our previous blog IP Addressing Fundamentals

Types of IPv4 Addresses

IPv4 divided into different types which are based on their usage and functions.

• Public IP Address – used to identify devices globally on the internet.
• Private IP Address – used for communication within a network.
• Static IP Address – it is a permanent address that does not change.
• Dynamic IP Address -   it’s a temporary address that changes automatically.

We already explained these IP address types in detail in our previous blog and part 1 of this series IP Addressing Fundamentals.

Range of IPv4 Addresses

The total range of IPv4 is from 0 to 255. Each octet store the value from 0 to 255.

0.0.0.0   to 255.255.255.255

It creates 4.3 billion unique IPv4 Addresses. In the beginning of internet 4.3 billion addresses seemed very large but with the massive growth of internet-connected devices such as:

• Mobile phones
• Computers
• Websites
• Smart TVs
• IoT devices
• Servers
• Cloud systems

The demand for IP addresses has increased and as a result IPv4 started running out.

We can say that billions of devices now need internet access, but the limited IPv4 addresses are no longer sufficient for modern devices needs.

To solve this problem multiple technologies were introduced such as:

• NAT (Network Address Translation)
• Private IP Addressing
• IPv6

These technologies were introduced to provide a much larger address space.

Importance of IPv4

IPv4 is most important in computer networking. It is the main protocol that helps devices to identify each other and exchange data using internet.

Let’s understand its importance using some major functions.

Every single device connected to the network needs a unique IP address which provides identification for the device.

It allows devices from multiple networks to communicate each other over the internet.

Internet access is depends on IPv4 because users browse websites, watch YouTube, use social media, send emails, play online games and many more , all smoothly happen because of the IP address.

Routers use IPv4 addresses to forward data packets to the correct destination devices

IPv4 addresses create a structured communication system in networking

Without IPv4, modern networking and communication over internet would not function properly.

Limitations of IPv4

Even with its importance, IPv4 also has several limitations.

It only supports 4.5 billion addresses which is insufficient for billions of other devices.

The rapid increase in technologies mobile, computer, and servers makes IPv4 addresses limited.

Also, IPv4 does not have a build-in encryption or any kind of security features, it uses additional technologies for protection such as VPN, firewall and IPsec etc.

The technologies used to manage IPv4 address shortages are increase the network complexity.

Interview questions to remember

Define IPv4?  

IPv4 stands for Internet Protocol version 4, which is a connectionless protocol and used for communication. It routes data packets from source to destination and provides logical addresses to devices inside a network.

Tell the full form of IPv4? 

IPv4 stands for Internet Protocol version 4, which is a connectionless protocol and used for communication.

Tell the number of bits in IPv4? 

Let’s take an example (192.168.16.25) this IP address divided into four parts means four octets.

• 1^st octet (192)
• 2^nd octet (168)
• 3^rd octet (10)
• 4^th octet (5)

Each octet contains 8 binary bits, so the complete structure becomes:

8 bits + 8 bits + 8 bits + 8 bits = 32 bits

Define an octet?  

An octet is group of 8 bits. IPv4 address divided into four parts, each part contains 8 bits therefore each part is called an octet.

Tell the number of octet in IPv4? 

(192.168.1.1) the address is divided into four parts (octets) and each part separated by dot, additionally each section contains a decimal value that ranges from 0 to 255.

Define network ID?

The Network ID is used to identify the network to which a device belongs to.

Define Host ID?  

The Host ID is used to identify a specific device inside a network.

Define public IP?    

Public IP Address is used to identify device globally on the internet.

Define private IP?

Private IP Address is used for communication within a network.

Why IPv4 is now limited?

The rapid increase in technologies mobile, computer, and servers makes IPv4 addresses limited.

Tell the uses of IP address?

IPv4 is most important in computer networking. It is the main protocol that helps devices to identify each other and exchange data using internet.

Define Static IP?

Static IP Address is a permanent address that does not change.

Define Dynamic IP?

Dynamic IP Address it’s a temporary address that changes automatically.

Define NAT?

NAT stands for (Network Address Translation). It allows multiple devices in a private network to share single public IP address.

Why we still use IPv4?

Internet access is depends on IPv4 because users browse websites, watch YouTube, use social media, send emails, play online games and many more , all smoothly happen because of the IP address. Without IPv4, modern networking and communication over internet would not function properly.     

Conclusion

IPv4 is the foundation of modern networking. It is used for communication over internet, allowing devices to exchange data and find other devices across local networks and global internet. Understanding the concept of IPv4, its structure, octets, binary representation, types, and parts is most important for beginners.

IPv4 was introduced years ago and it has become the standard protocol of internet. In simple words, without IPv4, devices cannot find other devices within a network and communication over the internet becomes impossible.

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