Every single device that connects to the internet needs some form of unique address that can be identified and located. IP addresses provide this functionality.

IP stands for Internet Protocol: the communications protocol that allows each machine to have a unique ID and pass packets of data between networks. IPv6 is the most recent version, and includes features that make a big difference to how IP addresses are organised.

IP addresses: the story so far

Before IPv6, there was IPv4. IPv4 was the first standardised, widely implemented version of IP, with development stretching back to the 1970s. A typical IPv4 address could look something like ‘’. But as the internet became rapidly commercialised in the 90s, it became clear that this ageing technology had some serious limitations.

How many IPv4 addresses are there?

IPv4’s 32-bit addresses theoretically put the maximum number of IPs somewhere around four billion. That may sound like a lot, but it’s a worryingly low number when you consider that there are already over seven billion people on the planet, let alone individual devices.

Inevitably, IP addresses have been running out. The core of IPv4 comes from a time when widespread personal computers and mobile devices were still the stuff of science fiction; it was never intended to provide the vast numbers of addresses required in a hyper-connected society.

The switch to IPv6: solving the address shortage

This is where IPv6 comes in. Developed by the Internet Engineering Task Force (IETF – an open standards organisation), IPv6 became a Draft Standard in December 1998, but only achieved full Internet Standard status in July 2017. Its aim was primarily to increase the amount of available IP addresses, and also provide some efficiency and performance boosts along the way.

IPv4 vs IPv6: more improvements

Technical benefits associated with IPv6 include hierarchical address allocation. This helps avoid fragmentation of IP addresses and makes more efficient use of the address space. Multicast addressing is also expanded, simplified and optimised, allowing network packets to be transmitted to multiple destinations simultaneously.

A major difference between IPv4 and IPv6 is packet header structure. You could think of the header like the addressed envelope that contains the letter (the packet). IPv6 does away with the more complex header structure of IPv4, with rarely used fields moved to optional extensions. The result is more efficient packet forwarding via routers and improved overall performance.

But what about all those existing IPv4 addresses? Do they still work alongside IPv6? IPv6 to IPv4 traffic was not originally designed to be possible, but the reality of the modern internet means a wide variety of technical solutions allow the two to cooperate perfectly. The real question is whether IPv6 will ever be the only choice for IP addresses.

How many IPv6 addresses are there?

Recognising the need for a massive boost in available address space, the IETF worked hard to ensure IPv6 never experiences the same exhaustion problem as IPv4. IPv6 is 128-bit, in theory providing a maximum of around 340 trillion, trillion, trillion addresses. An example IPv6 address might look something like ‘2001:0db8:85a3:0000:0000:8a2e:0370:7334’.

Needless to say, we won’t be running out of IPv6 addresses any time soon. But the jump to 128-bit isn’t the only change, with IPv6 also offering several upgrades over IPv4.

The future: will IPv6 replace IPv4?

With its comparatively minuscule address space, you might assume that IPv4 is dead and buried. But in reality IPv4 is in great health, still accounting for about 75% of all internet traffic. IPv6 adoption is creeping up, but it certainly won’t be replacing IPv4 overnight.

However, you might have seen in the news that the European body that distributes IP addresses, RIPE NCC, has now officially run out of IPv4 addresses. It joins the North American body, ARIN, which ran out of addresses in 2015. The other three global distributors are not far behind. Due to this, more and more providers will now be forced to turn to IPv6 addresses. This should lead to higher adoption and compatibility rates.

Network address translation (NAT) technology is a saving grace for IPv4’s longevity. It allows organisations to run thousands of devices behind a handful of public-facing IPs. Similar techniques have also been employed by internet service providers, reducing the number of addresses required by their customers.

Long term, though, it’s clear that IPv6 will come to dominate, even if IPv4 sticks around for a long time. The coming decades will likely see an ever-increasing demand for colossal quantities of IPs, with the internet of things (IoT) connecting everything from fridges to thermostats – and every IoT device will need its own unique address. Universal IPv6 connectivity will be required to meet this demand.

At Fasthosts, we offer IPv6 addresses on all our servers. Whether you’re running a Dedicated Server, a Virtual Private Server, a Cloud Server or a Bare Metal machine, it’s simple to assign multiple IPv6 addresses at no extra cost. Contact us now for more details on how we can provide your ideal server hosting environment.