China's so-called "IPv9" has a long, complicated history

Updated Aug 22, 2026, 8:00 AM EDT I’m Adam Conway, an Irish technology fanatic with a BSc in Computer Science and I'm XDA’s Lead Technical Editor. My Bachelor’s thesis was conducted on the viability of benchmarking the non-functional elements of Android apps and smartphones such as performance, and I’ve been working in the tech industry in some way or another since 2017. In my spare time, you’ll probably find me playing Counter-Strike or VALORANT, and you can reach out to me at adam@xda-developers.com, on Twitter as @AdamConwayIE, on Instagram as AdamConwayIE, or u/AdamConwayIE on Reddit. Sign in to your XDA account In the early 2000s, the alarm bells had already been sounded for approximately a decade that IPv4 addresses were running out. Its 4.3 billion possible addresses, considered unimaginably large, suddenly looked very finite, and the standardization of IPv6 was a process undergone from the mid 1990s up until its publication in 1998. Yet just a few years later, in the mid 2000s, rumors circulated that China was working on IPv9. The problem, though, was that no international body recognized it, and it seemed drastically different from the rest of the wider internet. However, it wasn't just the lack of recognition that caused problems. Back in 1994, on April Fool's Day, an IETF request for comment (RFC) numbered 1606 was published, titled "A Historical Perspective On The Usage Of IP Version 9." Reports of China's IPv9 caused a lot of confusion, as while people were aware of the IPv9 April Fool's joke, they also initially thought that it was merely a reference to that same joke a decade later. As an aside, it's an incredibly detailed memo for an April Fool's Joke, with my personal favorite part being the following: This, coupled with early problems with broadcasts storms tending to make patients blood boil, have led to a rethink on this whole procedure. Also, the requirement to wear the silly satellite dish hat has led to feelings of embarrassment except in California, where it is now the latest trend. This confusion was shared by Vint Cerf, often regarded as one of "the fathers of the internet." In an email sent to figures within the Chinese internet community, he wrote the following: What could this possibly be about? As far as I know, IANA [Internet Assigned Numbers Authority] has not allocated the IPv9 designation to anyone. IPv9 is not an Internet standard. Could you please explain what is intended here? Nearly two decades later, there's now a much clearer picture of what happened at the time and what IPv9 was and was not. The brief history of IPv9 IPv9 was technically assigned before Map of all 123 DNS root server instances (including local Anycast instances) at the end of 2006. Please note, that the markers are not accurately placed. The main purpose is to demonstrate the mass of the markers, not their position. E.g. the four markers which cover a big part of Honshū represent four root servers in Tokyo.Credit: Matthäus Wander When we talk about IP versions in conversation, the only two that really ever come up are IPv4 and IPv6. IPv5 was an experimental streaming protocol that basically ended up rolled into the rest of IPv4, but there was an experimental version 9 assignment dubbed "TUBA." Outlined in RFC 1347, TUBA stood for TCP and UDP with Bigger Addresses, though it was quickly abandoned as the IETF shifted focus to IPv6 instead. Enter Chinese engineer Xie Jianping in the late 1990s, who wanted to explore those initial ideas with a homegrown approach at the Institute of Chemical Engineering in Shanghai. In September 2001, China formally set up the Decimal Network Standard Working Group, appointing Xie Jianping as its head. The mandate was to develop an internet protocol with independent Chinese intellectual property, including an IPv9 address format and a numeric domain name system. By 2003, Chinese researchers had filed initial patents related to IPv9, such as a “new generation IPv9 protocol router” (CN2591884Y) and methods for allocating addresses using a fully decimal algorithm. It was clearly taking some technical shape by this stage, and international researchers caught wind of it in 2004 following the announcement that "IPv9 had been formally adapted and popularized into the civil and commercial sectors." However, Cerf's email to Chinese internet leaders saw a response that yielded some clues about what exactly was going on. Professor Hualin Qian of the Computer Network Information Center of the Chinese Academy of Sciences described IPv9 as a research project that turned out to have serious practical shortcomings and little support, according to reports at the time. Qian further stated that network experts from Fudan University, Shanghai, "do not know any deployment of IPv9 in Shanghai." Despite this response, August 2007 saw the Ministry of Information Industry define IPv9 as the "new generation internet." IPv9 was met with skepticism from both researchers and engineers in China and in the west. Xie Jianping, in an effort to protect his reputation, sued a journalist over criticism that was later judged to be defamatory in nature, given that it quoted social media users who insulted Xie Jianping's character. The court was careful about where it drew that line, though. Beijing's No. 3 Intermediate People's Court upheld the ruling in July 2015, and said that criticizing IPv9 from a scientific and technological standpoint was entirely normal, so long as it stayed objective. What crossed into infringement was the wording, not the substance, and the technical criticism itself was never found to be false. Xie later sued Tencent, alleging that QQ's user ID system violated an IPv9 addressing patent. The court ruled against him in that instance. Despite this vast history, few technical details were ever published by the working group itself, which has contributed to skepticism about its viability as a protocol. From China's perspective, IPv9 was a necessity. There were 13 DNS root servers in operation globally, where ten of them were in the United States, two of them in Europe, and one in Japan. Now, those root servers are globally distributed using Anycast, but several research papers focused on IPv9 have highlighted this past control that the United States held over the world's internet. Even now, ICANN controls the contents of those root servers via IANA, and ICANN is a non-profit organization in the United States. Technically speaking, it could still be beholden to U.S. interests. For reference, this kind of dynamic is also why RISC-V International is registered in Switzerland, as the country is neutral and a company will not be compelled to align with any given superpower. One number did more work here than any technical claim ever did. Xie said repeatedly that the decimal network would break the roughly 500 billion yuan China supposedly paid the United States every year in "internet usage fees," though the figure didn't originate with him. On 23 January 2008 the Central Party School's economics department published a report on accelerating the adoption of a homegrown next-generation internet, and Shen Yang spent more than eighteen months hunting down the full text before finding it on the working group's own website, at a URL ending in 5000yi.htm. Five thousand yi is 500 billion, so they had named the file after the number. It totals eight categories of supposed annual payments, arrives at 579.4 billion yuan a year, and then compares that to the silver China paid in indemnities after the wars of the nineteenth century. No such fee exists, though. What China actually pays is registration fees to APNIC, the regional registry for the Asia-Pacific, and that comes to somewhere around 11.5 million yuan a year, or roughly forty thousand times less than the number being quoted. There was a more immediate incentive, too. Six months after that 2004 announcement, an article went up on the finance portal Hexun titled, more or less, "Zhejiang University Insigma: the first IPv9 concept stock." Investigators searching the patent database found nine patents connected to Xie and IPv9, all tied to Zhejiang University in one way or another, and the chairman of the listed company Zhejiang University Insigma was, at the time, the president of Zhejiang University. The university's own involvement soured fairly quickly, mind. Pan Xuezeng, associate director of its computer systems engineering institute and one of the researchers who worked with Xie early on, told an investigation that the whole thing was meaningless, and that he and his colleagues were technical researchers who ended up being deceived. The April Fool's joke was the specification Xie Jianping said so himself IPv9 wasn't a nod to RFC 1606, but it wasn't an unfortunate collision with it either. Xie Jianping treated the April Fool's joke as his requirements document, and he put that in writing to a journalist who asked him directly. That journalist was Shen Yang, who ran a long investigation into IPv9 across late 2004 and early 2005. He asked Xie why the protocol was called version 9 when the IETF had never assigned that number to anything resembling it. Xie's answer (machine translated) was that the IETF had assigned it, and he listed the six technical indicators he had taken from the document: The RFC document lists all of IPV9's technical specifications: 1. 42-layer routing addresses. 2. Can directly allocate addresses to end users without resolution. 3. Can assign addresses to biotech applications like human cells, DNA, biological missiles. 4. Can assign addresses to the microscopic world like nanotechnology, such as micro-robots for medical treatment and special industrial and military applications. 5. Can assign addresses for integrated circuits, automotive electronics, modern homes. 6. Humanity's space exploration dreams. RFC 1606 proposed that IPV9 must allocate addresses for space communications, so we have reserved this space. He closed by saying those were the technical plan proposed by RFC 1606's IPv9, and that his team had already implemented them. Every item on that list is a joke, though. The 42 layers are Julian Onions being funny about hierarchy bloat. The medical nanotech is the passage about monitors injected into the bloodstream, the ones that boil patients during broadcast storms. The space communication is the bit about intelligent life in other solar systems and a faster-than-light transport stack, immediately followed by a line about parallel universes being the more pressing problem. Xie kept the entire thing and treated it as a technical specification. It wasn't one stray email, either. The Decimal Network Standard Working Group's own site hosted a reference table with the heading "RFC documents relating to IPv9 technology." Seven RFCs are listed, five of them the genuine TUBA-era documents you'd expect. The other two are RFC 1606 and RFC 1607, and they're given the full treatment, with RFC 1606 offered in English, in Chinese translation, and in an annotated Chinese version. The translation is complete and unedited, so the light bulbs requesting addresses from light switches are in there, as is the satellite dish hat, as is the line near the top reading "1 April 1994." RFC 1607, titled "A View from the 21st Century," went out on that same April Fool's Day in 1994, and it was written by Vint Cerf. So while Cerf was emailing Chinese internet figures to ask what this could possibly be about, the working group was hosting an annotated copy of his own April Fool's joke as background reading. Put to him directly, Xie's position was that IPv9 drew on the essence of RFC 1606 and RFC 1607 together, and that neither document was the joke everyone said it was. Both authors, though, disagree. Onions confirmed it was a joke, written because some of the IPv6 proposals under discussion in 1994 struck him as short-sighted and wasteful with address space. Cerf's version amounted to RFC 1606 having been recognized as an April Fool's joke a very long time ago. To be fair to Xie, the RFC carries no warning label beyond its date, and after all, the IETF's April 1 tradition isn't common knowledge outside of networking circles. He was reading it in 2005, though, a year after a Chinese developer writing as delphij had translated large chunks of it specifically to point out what it was, closing with "this is the academic research recognized by Zhejiang University? Speechless." Technical details are hard to find We have an overview, though From a technical standpoint, China's IPv9 is not an officially recognized Internet Protocol version but rather an experimental alternative addressing and naming scheme. Its design borrows from existing internet architecture (like DNS and TCP/IP) with a few key modifications. Its hallmark is the use of decimal numbers (0-9) in addresses, instead of the hexadecimal notation used in IPv6, and its support of up to 2,048-bit address space. In IPv6, addresses are 128-bit and written in hex (including letters A-F), which can be daunting to read and remember, and marks a rather significant departure from the IPv4 addresses most would be used to. In contrast, IPv9 proponents argue that purely numeric addresses are more intuitive. For example, an IPv9 address might look like a long string of digits rather than an IPv6 address like 2001:0db8:85a3::.... In reality, memorizing a 10 or 20 digit number isn't really easier than a hex string, but the idea is that every segment is decimal, aligning with how phone numbers or ID numbers are used. Most descriptions of IPv9 settle on a 256-digit address, which is that same 2,048 bits expressed in decimal, and allows for a frankly absurd 10^256 addresses. Even IPv9's own documents don't quite agree on that, mind, as one of the patents describes packing each digit into four bits rather than eight, which would halve the address. IPv6 is nowhere near as big, but still has the capability of creating billions of unique addresses for every person on Earth today. IPv6 is far from exhausted, and IPv9 introduces extra overhead with its larger packet headers and more complex routing for, realistically, little gain. In fact, Professor Hualin Qian, who we mentioned earlier, noted that addresses this large would slow down networking due to the bigger headers required and network address translation with IPv4 and IPv6. But the most distinctive aspect of IPv9 was its approach to domain name resolution, which differed greatly from what we know and have used for decades. This is where the "numeric domain name system" comes in to play, as the idea was that internet resources could be accessed via ordinary decimal numbers, rather than just textual URLs. For instance, one could type a string of digits corresponding to a phone number or an ID to reach a website or service. To enable this, the team behind IPv9 created a modified DNS system that intercepts all-numeric queries and resolves them through a special IPv9 root server network, essentially acting as an overlay. If a user entered a domain consisting only of digits, the query would be redirected to IPv9 root servers (operated within China) for resolution, mapping it to a IPv4 or IPv6 address underneath: hence why it was described as "compatible" with both of those protocol versions. That compatibility wasn't absolute, though. The team behind IPv9 released a tool that would allow for inter-communication, but NetEase reported that it required changing your system's DNS in order to resolve queries and was similar to "DNS hijacking." To quote the article via a machine translation: The commonly used IP address (IPv4 address) is a 4-digit base-256 number. For example, 64.233.189.104 is Google's IP address. Adding "104 + 256 × 189 + 256 × 256 × 233 + 256 × 256 × 256 × 64" gives you the number 1089060200. After installing the plugin, simply enter http://1089060200 in your browser to open Google. It appears that every few years, we learn something new about IPv9. As recently as 2018, Lou Peide, Vice President of Beijing Shenzhou Tiancai Technology Development stated that IPv9 offers geographic location and industry category as a part of the protocol, and can be deployed within a region or industry, with all aspects of the infrastructure being homegrown, China-developed tech. All in all, IPv9 is more of a localized adaptation of IPv6 rather than a whole new thing. It has no IETF or ICANN recognition, and was developed primarily as a point of digital sovereignty for China. In 2019, researchers Wang Yubian of the Department of Railway Transportation Control and Yuri Shebzukhov of the Department of International Relations, both at Belarusian State University of Transport, said that IPv9 allows systems to be "independent of the US Internet but [be] Internet compatible." China's own experts rejected IPv9 in 2006 The criticism came from inside Calling IPv9 China's attempt at its own internet implies the country was broadly behind it, but it wasn't. The sharpest criticism came from Chinese engineers, it started almost immediately, and in one case it was collected into a signed document and sent to the ministry. In March 2006 the National Informatization Expert Advisory Committee held a symposium on IPv9, and the working group presented and defended the technology in person. The resulting opinion was finalized that May and signed by more than a dozen experts, Hualin Qian among them. It's a pretty methodical dismantling, and all the more effective for how unexcited it is. An over-long string of digits is harder to remember, not easier. Decimal is only a way of writing an address down, so calling the network a decimal network on that basis, let alone claiming the computers ran decimal algorithms, was far-fetched. The security findings were the true teardown, though. The worry about backdoors in foreign-made core routers is legitimate, the committee said, and some argue a Chinese-built IPv9 router avoids it. But if China can build a high-capacity IPv9 core router, it can build an IPv4 or IPv6 one of the same capacity. It was never about the protocol, it was about mastering core router technology. The same goes for sovereignty; China had already set up a mirror root server, and a separate IPv9 network that didn't interconnect would leave foreign users unable to reach Chinese sites at all. As for the world adopting IPv9 and China inheriting control of its root servers, the committee wrote that off as wishful thinking. As it turned out, the people the project claimed as supporters weren't as on board as they were made to seem. Jiang Lintao, chief engineer at the ministry's telecom research institute, had criticized IPv6 as an upgrade rather than a real advance, and that was treated as evidence he backed IPv9. Shen Yang asked him directly, and Jiang's answer was that he had never expressed a view on IPv9 in any setting and they were welcome to check. IPv9 has no mainstream usage today That we know of, anyway Despite the multi-decade build-up, there is no evidence that IPv9 is actually in use anywhere within China today. In fact, the only usages of IPv9 that you can find today live inside of research papers and testbeds, with no major operating system supporting the protocol nor any major Chinese software. Essentially, it appears that it never moved out of the prototyping phase, likely given China's large focus on IPv6 in recent years. The paperwork tells the same story. Operating an internet domain root server in China is a licensed activity, and the list of institutions actually licensed has one entry, which is CNNIC. The decimal network had been claiming operational root servers since 2003 regardless, and by November 2008 state media was carrying an announcement jointly attributed to the Ministry of Information Industry and the "China Decimal Network Security Supervision and Administration Bureau," a body that a ministry official had already told Shen Yang could not exist, because domain administration has no second executive department. On that note, China's government has, especially since 2017, put full weight behind IPv6 deployment. A high-level action plan in 2017 aimed to make China's IPv6 network the world's largest by 2025. The Chinese government has been pushing local telecoms companies to speed up their IPv6 rollout, and those companies had a deadline in July 2025 that saw them entirely blocked from deploying new NAT44 hardware. China now aims to be a leader rather than a separate entity to the rest of the internet, and has put resources into exactly that. IPv9's very existence highlighted a number of key problems with the internet as a whole, and its origins come from more of a political school of thought rather than a technical one. In many ways, the issues IPv9 raised, like control of root servers, local autonomy, and global interoperability, have been addressed through other means since then, as the question of digital sovereignty is an important one. ICANN's direct U.S. oversight was ceded in 2016, and the global spread of root servers implemented via Anycast provide countries more agency without abandoning global standards. Some DNS technology, like Yeti-DNS, allows countries who want their own sovereign DNS to essentially declare their own root servers, which would allow a country to essentially achieve a core aim of what IPv9 wanted to do. It's unlikely IPv9 will ever see any kind of large scale adoption, and the world has coalesced around IPv6 as the future of IP networking with China investing a huge amount of resources. For the country to suddenly pivot would incur a massive cost, and for ultimately no gain, either. A future "alternative internet" proposal would be more likely to surface as a globalized collaboration. China's "New IP" proposal (developed by Huawei and a subsidiary) has received criticism for carrying the risk of enabling even easier internet surveillance, but researchers from the SCION group at ETH Zurich have been less bashful. The team wrote that "Huawei identifies several valid problems of today's Internet and tries to propose solutions for some of them."