IPv4 vs IPv6: What’s The Difference, And Should You Care?


Bart Keating


2019 November 19th


If you're an avid consumer of tech news, you might well have heard of the internet's IP address crisis. In short, the organization that kind of runs the internet (ICANN) has run out of new IP addresses to hand out.

And this is kind of a big deal.

So, a new address system called IPv6 is here to help. It's an improvement on the regular IPv4 addresses. But what does the difference between IPv4 and IPv6 mean for you?

Which should you use and how can you ensure you're ready to deal with IPv6?

In this article, I'll answer those questions. These are the main things you should know when comparing IPv4 vs IPv6:

What is an IP?

IP stands for Internet Protocol and, put simply, is what allows the internet to function.

And, no, I'm not exaggerating.

IP provides the communication structure necessary for computers to talk to one another through the web. It's a way of standardizing the packets of information every internet-connected device sends and receives.

The body responsible for distributing IP addresses is known as ICANN, which stands for the 'Internet Corporation for Assigned Names and Numbers'.

IPv4 vs IPv6 ICANN

Whenever a packet is transferred over the internet, it will contain two IP addresses: that of the sender and that of the receiver. That means it's important every device connected to the internet is assigned an IP address.

It doesn't have to be a unique address though (more on that later), as it can be shared across a local network.

IPv4 vs IPv6: What is IPv4?

IPv4 is short for Internet Protocol Version 4. It's still used by the vast majority of modern internet-connected devices but was actually introduced in 1983. IPv4 addresses look like this example: 191.113.485.213. The key thing to know about IPv4 is that it's a 32-bit system. Bits are a unit of information used in binary counting.

Any computer experts reading this will already be familiar with binary, but all that matters here is that the number of bits the system uses determines how many addresses it can create.

For example, a 4-bit address system can contain 24, or rather 16, different addresses. Similarly, the 32-bit IPv4 system contains 232 addresses. That works out to just over four billion IP addresses!

4 billion sounds like an awful lot doesn't it? But here's the problem: we've run out of IPv4 addresses!

Remember, there are nearly 8 billion people in the world, so IPv4 doesn't have the capacity to assign each person a unique address.

Compounding the problem is the fact that, back in the 80s, some ISPs were assigned literally millions of IP addresses they didn't need which led to a ton of unassigned IPv4 addresses going to waste.

The Difference Between IPv4 and IPv6

Unlike IPv4 addresses, which are purely numeric, IPv6 addresses actually contain letters as well as numbers. 2009:0th2:12b5:0000:0001:6s6n:0818:8449 is an example IPv6 address.

The key improvement IPv6 offers over IPv4 is the number of addresses it contains. IPv6 is 128-bit, so there are 2128 possible IPv6 addresses. 

That's approximately 340 undecillion different combinations. What's an undecillion? Picture a 1 followed by 35 zeros. So, a total number of possible combinations is, wait for it:


Essentially, the world won't run out of IPv6 addresses anytime soon!

The Benefits of Using IPv6

Because of the vast number of possible addresses, if every internet enabled device was using IPv6, each one could be given a unique address. With IPv4, devices on the same network share the same IP address. The Network Address Translation (NAT) technology which allows them to do that can be a weak point for hacking attacks, so IPv6 will bring security benefits by eliminating the need for it. 

IPv4 vs IPv6 ConflictAnother advantage of IPv6 is that it will eliminate the possibility of IP address collisions.

These are errors that occur when two or more devices on the same network aren't able to distinguish one another properly.

Normally they're quite simple to fix - but with IPv6, this problem completely disappears, and you get less buggy networking.

IPv6 is also a better tool for multicast routing. Multicasts are used by streaming services to broadcast a single data copy to a well-defined set of individual addresses. IPv6 is a far more appropriate format for multicasts because the streaming host knows in advance that each IP address only represents a single device.

Theoretically, because it uses simpler data headers and is more optimized for peer-to-peer traffic, IPv6 should also offer performance benefits over IPv4.

However, recent performance comparison studies haven't shown a big difference between the two protocols. That may well be because IPv6 connections are hampered by a lack of compatible infrastructure.

So, we can expect tangible speed improvements over time as technology catches up.

IPv4 or IPv6: Which One To Use?

After reading about all of the benefits of IPv6, you might think this is an irrelevant question, but IPv6 is the obvious choice, right?

Well, not necessarily. Despite all the networking improvements it provides, only 5% of the internet is currently using IPv6.

IPv6 uptake remains low because upgrading to an IPv6 system requires new networking hardware and software, making it expensive for internet service providers to make the switch. Worse still, IPv6 isn't backward compatible so, if you want to run an IPv6 friendly website, you'll also need to maintain an IPv4 version too.

Because IPv6 is so uncommon, internet companies are unlikely to start rolling out updates that take advantage of it anytime soon, as only a minority of users will notice the difference. In effect, as a consumer, the costs of upgrading are likely to outweigh the benefits in the near future. 

IPv6 usage is only going to increase in the future though. So if you run a business that operates a large networking system, you should start future-proofing by investing in IPv6 tech now as your update may take months, or even years to complete.

What Do I Need for IPv6?

To have IPv6 enabled, you need a compatible operating system, and a router as well as ISP with IPv6 support. And as a matter of fact, you might already be using an IPv6 system without realizing it.

Before you consider upgrading, you should find out if you are by checking your connection's IPv6 support with a testing service.

IPv6 connections are more common in richer countries where internet service providers have the resources available to buy new equipment. So if you're located in a tech hub city, the chances that you are already using IPv6 are significantly higher. 

If, when you test it, you find your internet connection is only compatible with IPv4 addresses, you will need all of the following to make the swap to IPv6:

  • IPv4 vs IPv6 Windows SettingsAn operating system that supports IPv6: This is the easy one.
    Every recent iteration of Windows, Linux, and Mac OS X comes with IPv6 compatibility as standard.
  • An IPv6 compatible router: Lots of routers now include IPv6 compatibility, but many don't have it turned on by default.
    It's worth double checking the specs of your current router (as you may be able to enable IPv6 connections within its settings menu) before you head out and purchase an expensive upgrade.
  • A subscription to an IPv6 friendly ISP: Because of its slow global uptake, a large number of ISPs haven't invested in new IPv6 hardware yet.
    Make sure you check if yours has before you bother changing your personal networking equipment.

IPv4 vs IPv6 - Final Note

Whether you run a personal or business network system, it's important to remember that sooner or later, the majority of web companies will make the switch to IPv6. When that happens, upgrading will be essential if you want to maintain compatibility with the services you use every day.

To decide whether or not to upgrade to an IPv6 system, ask yourself whether you'd prefer to spend the cash to future-proof yourself now, or wait until IPv6 equipment costs have fallen and risk having to rush through the changeover process.

What do you think about the IPv4 vs IPv6 debate? If you made the changeover, I'd love to hear about your experience. Please tell me if you have noticed the benefits by commenting below!

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