The group which administers internet addresses in Europe has said it has now run out of addresses which use the IPv4 system.
RIPE, the consortium of internet organisations that oversees the system of assigning internet addresses in Europe, said it has begun allocating from the final block of 16.8 million IPv4 addresses - which were allocated by the Internet Assigned Numbers Authority (IANA) to each of the five Regional Internet Registries (RIRs) in February 2011.
Axel Pawlik, Managing Director of the RIPE National Cordination Centre said: "When the internet was first designed, it seemed highly unlikely that IP address space would ever be an issue. However, the limitations of the pool of IPv4 address space became clear over time, and in the last few years we have been monitoring supplies closely, preparing ourselves and all stakeholders for the next stage of the Internet.
"Reaching the last [batch of addresses] underlines the importance of IPv6 deployment, which is vital to the future growth of the Internet."
The replacement system, IPv6, which creates 340 trillion, trillion, trillion addresses, has begun to roll out, and IPv6 Day was held in June of this year.
At the time, Vince Cerf, seen as one of the fathers of the internet, said: "The internet was designed in 1973 and was launched in 1983 and in that time frame we thought it was an experiment. So we allocated address space sort of like telephone numbers sufficient to define 4.3bn termination points,"
Pawlik added: "More than 50 percent of our members already have an IPv6 address space allocation, but there is still a long way to go before we can say that everyone is prepared."
When IPv6 will mean little or no change for the end-user, internet service providers (ISPs) and large businesses will need to invest in new hardware and software.