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IPv4 vs. IPv6: A Comparison

James Gallagher - September 21, 2020

The Internet Protocol (IP) is used to send data around networks on the internet. There are two modern versions of the Internet Protocol that you may hear in use: IPv4 and IPv6.

In this guide, we’re going to discuss what the Internet Protocol is and what IPv4 and IPV6 are. We’ll discuss the similarities and differences between these two protocols so you can develop a deep understanding of how they are used today.

What is Internet Protocol?

Every device connected to the internet has its own IP address. This IP address uniquely identifies a device from all of the other devices out in the world.

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Using this IP address, the Internet Protocol can transmit data to other members of the network . The Internet Protocol sends information called packets across networks. Packets may contain data about web pages, files, or other data that is being sent over the protocol.

The Internet Protocol is a protocol because it describes a list of standards your computers must follow to make connections. These standards make sure every device on the internet is using the same technique to connect to each other.

IP addresses, which are assigned by Internet Service Providers (ISPs), can change. When you use a different network, your IP will change because your connection will be provided by another ISP. This means, unlike your real name, your IP address may change often.

What is IPv4?

Most IP address you encounter uses the following format:

This format is called an IPv4 address. IPv4 is the first version of the Internet Protocol, even though its name would suggest it is a more modern iteration. Today, IPv4 is the most widely used way of identifying devices on a network.

An IPv4 address has four numbers. Each of these numbers is separated by a full stop (.). The numbers in each section of the IP address must be between 0 and 255.

Because numbers can range from 0 to 255, there are a massive number of addresses that can be assigned. To be more precise, 4.3 billion addresses are available.

What is IPv6?

What if we were to tell you the world is running out of IP addresses? But we just said that there were plenty to go around, right? Due to the growth of the internet, the world has started to see a shortage of IP addresses.

The internet of today is unlike what the internet was when it was first invented. Toward the start of the internet’s history, most people connected to the internet on one device: a home computer.

We now have mobile phones, wearables, and other electronic devices we connect to the internet. It’s not uncommon for one person to have multiple internet-connected devices in their homes.

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That’s why IPv6 was introduced. IPv6, unlike IPV4, uses 128 bit addresses. This means IPv6 introduces the possibility of assigning many more IPs.

To be exact, 340,282,366,920,938,463,463,374,607,431,768,211,456 IP addresses are available under IPv6. The hope with IPv6 is that we will never run out of IP addresses. It’s hard to imagine a world where so many devices could be connected to the internet.

Let’s take a look at an IPv6 address:


This example is sourced from Wikipedia . This IP address looks very different to the IPv4 address we discussed earlier. In an IPv6 address, there are eight groups of characters. These groups each represent hexadecimal codes.

In each group, there are four possible characters or numbers that can appear.

IPv4 vs. IPv6

The biggest visual difference between IPv4 and IPv6 is the size of the numbers. IPv4 uses a 32-bit address whereas IPv6 uses a 128-bit address. This, as we discussed, means IPv6 can support a significant amount more addresses.

IPv4 uses periods to separate each of the numbers in an address whereas IPv6 uses colons.

There are technical differences between these two addresses.

IPv6 is more efficient at routing packets to their destinations. What’s more is that IPv6 comes with a more simple packet header. With that said, there is almost no evidence to suggest that there is a significant difference between the connection speeds on these two networks.

IPv6 comes with new security features unavailable in IPv4. There are strict authentication and verification procedures in IPv6 designed to protect packets of data. We’ll not delve too deep into these protections because they can get technical very fast.

IPv4 is the most widely-used implementation of the Internet Protocol. Although, the adoption of IPv6 is rising fast. According to Google’s IPv6 Project , 29.55% of the world has adopted IPv6. This is not an insignificant number given how many devices there are on the internet.


The Internet Protocol lets networked devices transmit information. Every device on a network is assigned a unique number called an IP address. This identifies each device.

Initially, IP addresses were assigned using a protocol called IPv4. This was sufficient for a while until more devices started to connect to the internet. Today, IPv6 is in wide use, which offers more addresses than we could possibly use. This protocol should protect us from the problem of running out of IP addresses.
Now you have the knowledge you need to compare IPv4 and IPv6 like a networking pro !

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James Gallagher

About the author: James Gallagher is a self-taught programmer and the technical content manager at Career Karma. He has experience in range of programming languages and extensive expertise in Python, HTML, CSS, and JavaScript. James has written hundreds of programming tutorials, and he frequently contributes to publications like Codecademy, Treehouse,, Afrotech, and others.

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