With networks you run into the terms IPv4 and IPv6. People say IPv4 addresses are running out and the future belongs to IPv6. What does that mean and do you have to do anything about it? Let us explain without unnecessary technicalities.

In brief: what an IP address is

An IP address is the address of a device on a network, by which devices find their way to each other. IPv4 and IPv6 are two versions of what these addresses look like.

IPv4: the original system

IPv4 is the version most people know: four numbers separated by dots, for example 192.168.1.1. The problem is that IPv4 offers only about 4.3 billion addresses, which once seemed endlessly many, but today is no longer enough.

Why IPv4 is running out

There are far more devices connected to the internet today than available IPv4 addresses: computers, phones, TVs, cameras, the smart home. This is partly solved by NAT, which hides a whole network behind one public address, but the addresses are running out anyway.

An IPv4 address is technically 32 bits, which gives the roughly 4.3 billion combinations mentioned. NAT fits dozens of home devices behind a single public address, but that is only a delay. The addresses have run out in the meantime and new providers find them harder to obtain.

IPv6: the solution for the future

IPv6 brings a much longer address written differently, for example 2001:db8::1. The address is 128 bits, so the number of combinations is astronomical (a number with 38 zeros). There is therefore a practically inexhaustible supply of addresses and every device can have its own. This removes the pressure of an address shortage and simplifies some things.

The benefits of IPv6

  • A huge range. There are so many addresses that a shortage is nothing to worry about for a very long time.
  • The end of NAT. Every device can have its own public address, so the complicated hiding of a network behind one address goes away.
  • Better routing. IPv6 was designed more cleanly, which can in places simplify the path of data across the internet.

Why the switch is so slow

Even though IPv6 has been available for years, the switch is slow. IPv4 and IPv6 are not directly compatible with each other, so operators must keep both systems running at once for a while. On top of that, NAT long “rescued” IPv4, so there was no great pressure for a fast change. That is why the switch drags on and both systems will keep running side by side for a long time.

The main differences

  • The number of addresses: IPv4 has them limited, IPv6 practically unlimited.
  • The notation: IPv4 are numbers, IPv6 is longer and also uses letters.
  • NAT: with IPv6 it is less needed, because there are enough addresses.

Do you as an ordinary user have to do anything?

In most cases no. The switch happens gradually and both systems run at the same time (so-called dual stack), so everything works automatically. Modern devices and operators support IPv6. Occasionally IPv6 even helps with remote access home, when you have a problem with CGNAT.

Dealing with a network, remote access or addressing in a company? Get in touch, we will design it correctly. You will find more terms in the article networking basics.

This article is part of our Computer networks overview.