Press Release

Press Release

20 October 2010

Marissa Ramey

ARIN Recognizes Interop for Returning IPv4 Address Space

ARIN to reallocate address space to other organizations, continues to emphasize the need for IPv6 adoption

Chantilly, VA, October 20, 2010 – The American Registry for Internet Numbers (ARIN), a nonprofit association that manages the distribution of IP addresses and other Internet number resources, today recognizes Interop, an organization with a long-standing presence in the Internet industry, for returning a significant portion of its Internet Protocol version 4 (IPv4) address block.

Interop was originally allocated about 16 million IP addresses (called a “/8” or “slash-eight” block) before ARIN’s existence and the availability of smaller-sized address blocks. The organization will continue to use a small portion of the original allocation, and return the remainder to ARIN for the greater good of the Internet community. The announcement comes at the Interop New York conference, taking place this week.

“We want to thank Interop for returning its unused IPv4 address space to ARIN, and therefore allowing those addresses to go to other organizations that need them,” said John Curran, President and CEO of ARIN. “ARIN encourages any other organizations with excess IPv4 address space to return it, as it will benefit the Internet community as a whole.”

ARIN will accept the returned space and not reissue it for a short period, per existing operational procedure. After the hold period, ARIN will follow global policy at that time and return it to the global free pool or distribute the space to those organizations in the ARIN region with documented need, as appropriate.

With less than 5% of the IPv4 address space left in the global free pool, ARIN warns that Interop’s return will not significantly extend the life of IPv4. ARIN continues to emphasize the need for all Internet stakeholders to adopt the next generation of Internet Protocol, IPv6.

“Interop is pleased to serve as an example for other network operators as we complete our transition to IPv6,” said Lenny Heymann, Interop General Manager. “Our mission at Interop is to highlight the incredible changes in the industry and help plan for what comes next. The transition to IPv6 is a critical step for the future of the Internet – one that will surely bring with it many more changes and exciting new opportunities.”

“Even with this additional space, we still have less than a year until we’ve exhausted the pool of IPv4 addresses. All network operators should take responsibility for the future sustainability of their networks and start preparations now for making their public facing servers IPv6 reachable,” added Curran.

About the American Registry for Internet Numbers

ARIN is the nonprofit corporation that manages the distribution of Internet number resources – IPv4, IPv6, and Autonomous System numbers – in its service region, which includes Canada, many Caribbean and North Atlantic islands, and the United States. More information on IPv6 adoption is available at and

About Interop

Interop® drives the adoption of technology, providing knowledge and insight to help IT and corporate decision-makers achieve business success. Part of UBM TechWeb’s family of global brands, Interop is the leading business technology event series. Through in-depth educational programs, workshops, real-world demonstrations and live technology implementations in its unique InteropNet program, Interop provides the forum for the most powerful innovations and solutions the industry has to offer. For more information about these events, visit