ESnet Celebrates 25 Years of Production IPv6 Networking

Left: The American Registry for Internet Numbers record showing the first block of IPv6 addresses, issued to ESnet 25 years ago today. Right: the original DEC Alpha Personal Workstation running hershey.es.net, believed to be the first computer on the production IPv6 network — which still runs and sits in Michael Sinatra’s office at ESnet (read his blog post on today's anniversary).

Twenty-five years ago today, on August 3, 1999, IPv6 history was made: ESnet was issued its first IPv6 production netblock (range of IP addresses), which is still in use today. This was the first production IPv6 address allocation in North America — and possibly the world.  

The American Registry for Internet Numbers (ARIN) assigned the very first block out of its 2001:400::/23 allocation, and since then, ESnet has numbered its production IPv6 services out of 2001:400::/32.*   

Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP) used to locate computers connected via communications networks and to route traffic across internet connections. As the Internet grew in popularity in the 1990s, its architects realized that address space would soon become exhausted, due to flawed methods of allocation as well as a general lack of planning for the network's popularity. Work on the IPv6 standard began in 1995, in order to widen the addressing scheme (e.g., 128-bit addresses) and allow 2¹²⁸ , or approximately 3.4×10³⁸ total addresses. 

The IPv6 standard was developed by the Internet Engineering Task Force (IETF) in the 1990s as a replacement for IPv4 and fully ratified in 1998. It has been in an extended process of supplanting IPv4 ever since. By the end of fiscal year 2025, the U.S. government is requiring that all agencies to migrate 80 percent of their assets off of legacy IPv4. 

ESnet staff have been key drivers of IPv6’s development since the very beginning. That’s why ESnet received the first public production IPv6 addresses 25 years ago today, helping to usher in a new era for the Internet. ESnet continues to promote IPv6 across the national laboratory complex — co-leading both the Department of Energy’s IPv6-only Implementation Team and its community of practice groups — as well as across research and education networks worldwide.

For an entertaining deep dive into the history, context, and key players in this IPv6 milestone, read the new blog post “25 Years of Production IPv6 in ESnet,” by ESnet network engineer and IPv6 expert Michael Sinatra.

Learn more:

• Designing, Constructing, and Operating an IPv6 Network at SC23: A case study in implementing the IPv6 protocol on a heterogenous network that supports the SC23 conference, July 2024 paper by ESnet network engineers Kate Robinson and Jason Zurawski and Argonne National Laboratory’s Tom Costello
• Papers and presentations for IETF by ESnet’s Nick Buraglio, co-chair of the IETF IPv6 Operations group 

*The netblock would have originally been a /35, later increased to /32 automatically by the RIRs.