World IPv4 Stocks Finally Run Out

Today marks the beginning of the end of the Internet as we know it. This morning, the Internet authority IANA allocated two batches of IPv4 addresses to APNIC, the regional Internet registry of the Asia Pacific, leaving just five batches (known as /8s) in the global pool.

Some time ago, the regional Internet registries (RIRs) agreed that, when IANA got down to the last five /8s, the organisation would allocate them automatically to the five RIRs, regardless of whether or not those registries needed more IP addresses at the time. That day has arrived, meaning that IANA’s stock of IPv4 addresses is now fully depleted.

Endgame plans

IP addresses are unique online identifiers made up of four number groups, allowing computers to communicate with each other around the world. The Internet is built around version four of the IP addressing scheme (IPv4) which can accommodate around 4.3 billion addresses.

When the web was set up in the 1970s, 4.3 billion seemed like more than enough, but the growth of the Internet – in particular the recent surge in demand from Internet-connected mobile phones, e-readers and other devices – means they are being used up faster than ever. Nigel Titley, chairman of the regional Internet registry for Europe, the Middle East and parts of Central Asia (RIPE NCC), predicts that new IPv4 addresses will run out completely in September 2011.

“We have endgame plans in place for those last /8s,” said Titley (left), speaking to eWEEK Europe. “We will set about half a percent of that final /8 aside for unforeseen circumstances, just in case something comes along that we absolutely need IPv4 for. After that, every local Internet registry (LIR) will be entitled to a single /21 out of that last /8, if they can produce evidence that they have IPv6 transition plans in place.”

Adopting IPv6

In the knowledge that the IPv4 system would eventually fall short, the IPv6 standard was developed in the early 1990s, and completed in 1994, when the addresses were first predicted to run out. The new version allows trillions of new IP address combinations, because it uses 128 bits of address data, giving it much greater capacity to accommodate the growth of the Internet than IPv4 addresses, which contain only 32 bits.

Despite providing substantially more address space, IPv6 has no direct commonality with IPv4, so a single-stack IPv6 machine cannot talk to an IPv4 machine. The two protocols will therefore have to run in parallel – or dual stack – for some time, in order to avoid breakages in the network.

“The two protocols can coexist, but they can’t intercommunicate,” explained Titley. “Gradually, as IPv6 usage ramps up, IPv4 usage will ramp down. And eventually it will get to a point where we envisage retiring IPv4 altogether.”

However, according to Clive Longbottom, head of research at analyst firm Quocirca, the lack of pressure on service providers to move to IPv6 could prevent this transition from running smoothly. The Internet is still predominantly IPv4-based, and the co-existence of IPv4 ad IPv6 relies heavily on Network Address Translation (NAT), which limits the performance of the Internet.

“IPv6 is a chicken and egg problem,” said Longbottom. “To lower the number of IPv4 addresses in use, a full IPv6 public backbone is required. It is assumed that this will take around 10 years – and we’ve left it too late now.”

“IPv4 address scavenging is the only way forward now – we have to be able to harvest addresses that are not being used and be very careful in how we make these available for use,” he added. “Mass spammers and other blackhats using IPv4 addresses for a matter of minutes have to be a prime target.”

Is the world ready?

One advantage of the IPv6 protocol, according to the RIPE NCC, is that it is less vulnerable to brute force scanning attacks, due to the enormous number of IP addresses (3.4 trillion trillion trillion, to be precise). “Because there are so few IPv4 addresses, you can actually try every address in sequence and see if anything is there, whereas with IPv6 there are so many addresses that it’s just not practical,” said Titley.

Tech giants Facebook, Google and Yahoo have all agreed to take part in ‘World IPv6 Day’ on 8 June 2011, when they will enable IPv6 on their main services for a 24-hour “test flight”. They join content delivery networks Akamai and Limelight Networks, as well as the Internet Society, in an attempt to motivate organisations across the industry to prepare their services for the imminent transition.

According to Leslie Daigle, the Internet Society’s chief Internet technology officer, the day will be a test of “whether the world is ready for IPv6.” If the test is successful, essentially nothing will happen – but ISOC will be providing web tools and apps for people to monitor the day and watch it happening.

The coalition government last year helped to launch 6UK, a non-profit organisation set up to lead the country’s transition to IPv6. For further information, and advice for companies on IPv6 adoption, visit the 6UK website.