European companies are not being pressed to accelerate IPv6 deployment according to the European Internet registry.

RIPE NCC was responding to news that ARIN, the US Internet registry, had been sending out letters to companies applying for domain names warning them that the stock of IPv4 addresses would be running out within two years and that companies should be hastening their adoption of IPv6, the emerging standard for Internet communication.

ARIN Chairman John Curran wrote in a letter dated 15 April, that from 18 May, it expected companies to "begin planning for IPv6 adoption if not doing so already." It also said that applications for IPv4 addresses to include an "attestation of accuracy from an organisational officer." The full letter was posted on the SANS Internet Storm Center blog.

The agency went on to say that it was taking this step "to ensure the legitimacy of all IPv4 address space requests" so those organisations with a legitimate need for address space could still get it.

It was not an approach that appealed to its European counterpart. Axel Pawlik, managing director of the RIPE NCC, said: "We ensure that the management and distribution of Internet number resources is undertaken as effectively as possible. This is achieved while taking into consideration the cultural and economic differences between these regions. A letter to inform ISPs of the need to accelerate IPv6 deployment may work for ARIN in the US and Canada, however we would not find it an effective way to communicate with our members in our service region."

He agreed that it was important to hasten the acceleration, but stressed the importance of co-operation between all parties.

"It's expected that IANA will distribute the last blocks of IPv4 in late 2010, and all of the five RIRs will run out of IPv4 address space about a year later. It is therefore important that the RIRs work closely together and with the rest of the Internet stakeholder community to ensure an efficient deployment of IPv6 worldwide and help safeguard the future development of the Internet. Our operations and procedures are fully audited by our members and third parties. As a result we are confident that they are appropriate, effective and beneficial for our members and the region we serve."

There has a been a marked reluctance to upgrade to IPv6. In March, a survey by the Internet Society found that there had been no concrete business drivers for IPv6, so take-up had remained patchy. In the same month, a survey by Pingdom showed that just 0.25 percent of Internet traffic was IPv6.