Every IPv4 address is now allocated and could run out within weeks

It's official: the IPv4-based internet is full, or at least it will be within a few weeks.

There are no more IPv4 addresses left to allocate, after APNIC, the Regional Internet Registry (RIR) for the Asia-Pacific region grabbed two blocks and the remainder were allocated equally between the five RIRs. ISPs will still be able to request IPv4 addresses from their RIR until the pool has been depleted, which could be a matter of weeks. A campaign is underway to persuade website owners to switch to the new addressing system, IPv6.

Raul Echeberria, chairman of the Number Resource Organisation (NRO), the official representative of the five RIRs. said: "Depending on address space requests received, this could last each RIR anywhere from a few weeks to many months. It's only a matter of time before the RIRs and ISPs must start denying requests for IPv4 address space. Deploying IPv6 is now a requirement, not an option. All internet stakeholders must now take definitive action to deploy IPv6."

ICANN's chief executive Rod Beckstrom said, "The adoption of IPv6 is now of paramount importance, since it will allow the internet to continue its amazing growth and foster the global innovation we've all come to expect."

Q&A: What does the end of IPv4 addresses mean? Source: Sebastien Lahtinen, co-founder of broadband news site thinkbroadband.com

How many IPv4 and IPv6 addresses are there?

There are approximately four billion IPv4 addresses, however not all of these can be used openly on the internet. There are so many IPv6 addresses that each human being could have trillions of addresses

IPv4 = 4,294,967,296 addresses

IPv6 = 340,282,366,920,938,000,000,000,000,000,000,000,000 addresses

When will IPv4 finally run out?

This depends. IP addresses are distributed through registries and service providers to internet users, so it will take some time before each level runs out. We will start seeing some of the effects within weeks or months. We are now seeing final allocations from IANA to the Regional Internet Registries (RIPE in Europe), who will distribute them to Local Internet Registries (typically network operators/service providers) who will then assign space to users.

What happens when IPv4 runs out?

It is likely that network operators will try to free up unused IP addresses in the short term, but there will be an increasing push for IPv6 adoption.

There are also several systems designed to help in the transition between IPv4 and IPv6 to increase interoperability. We are likely to see increased use of Network Address Translation (NAT), which allows IP addresses to be shared by a number of users, something mobile broadband companies have already been using for many years on a large scale.

How do I use IPv6?

Most modern operating systems support IPv6 out of the box, including Windows 7, Windows Vista, the latest Apple Mac OS X and most Linux systems. Some older systems including Windows XP may require some additional configuration.

You also need to ensure your broadband router is IPv6-enabled. Most consumer routers currently are not supporting native IPv6, so make sure your next router does. Finally, you need to ensure your ISP supports IPv6.

How difficult is moving to IPv6 for consumers?

Moving to IPv6 should be a process that happens gradually when you upgrade equipment and there are transitioning provisions in place that will ensure interconnectivity between IPv4 and IPv6 network. This means that consumers have no need to panic; this is not a Millenium Bug situation.

Consumers don't generally have to interact with IP addresses directly, as the internet uses domain names which are more memorable for users, which are translated into IP addresses. These domains can have both IPv4 and IPv6 addresses.