Overview of IPv6 adoption in the Netherlands lost

Because reliable quantification of Dutch IPv6 adoption is much more difficult than it used to be, the task of developing policies to encourage further adoption is also more challenging. And legislating to mandate IPv6 support is more daunting still. What's more, any such initiatives would depend on effective means of measuring the effects of the measures taken.

The problem has also taken on a structural character, because the adoption of IPv6 in the Netherlands no longer has a problem owner. "Large-scale implementation of IPv6 is important for the continued growth and future-readiness of the internet. We really have to guard against squandering our lead position in the internet infrastructure field through neglect and false economisation. We have been warning for years about the Netherlands' sluggish adoption of IPv6, and about the implications both for the accessibility of our internet market and for our investment climate.

Urgent need for IPv6

We need to switch to IPv6 – the latest version of the Internet Protocol, which forms the basis of all traffic on the internet – as soon as possible. Although IPv4 is now more than 40 years old and technically outdated, it's still used by two thirds of internet users. The biggest problem with IPv4 is that the available address space was used up years ago. Because they are in very short supply, IPv4 addresses are increasingly expensive. We also see widespread use of (CG)NAT, a stopgap workaround that causes connection problems and has fundamental implications for the utility of the internet.

The need for migration is particularly acute in the Netherlands, because we currently lag behind neighbouring countries and the rest of the world where IPv6 use is concerned. Sluggish adoption of IPv6 is damaging the Dutch economy. It makes the Netherlands less attractive for initiatives with the Internet of Things (IoT) and tarnishes the country's image as a business-friendly innovation centre.

Client side

Eighteen months ago, some important statistics relating to Dutch adoption of IPv6 became unusable. First, there was the data on the number of Google users accessing the company's services by means of an IPv6 connection, published on Google's IPv6 Stats page. Google's data used to show that about 35 per cent of Dutch users were connecting with IPv6, and that the percentage was gradually increasing. Then, in the summer before last, the published figure suddenly dropped to less than 10 per cent! As the chart below shows, the latest number (January 2024) is 23 per cent.

Figure 1: Dutch client-side IPv6 adoption according to Google, January 2024.

Figure 2: Dutch client-side IPv6 adoption according to Google, March 2022.

Figure 3: Dutch client-side IPv6 adoption according to Google, September 2023.

Strange developments

We've long known that the Netherlands lagged behind neighbouring countries on IPv6 adoption [1, 2]. On the client side, the main reason was that neither of the country's 2 big internet access providers – KPN and Ziggo – offered a proper IPv6 service to its customers. However, Google's recent adoption data looks quite implausible. For one thing, it marks a sudden departure from the general consensus: the statistics published by the various IPv6 testers used to be broadly in agreement. The word on the grapevine is that Google's IPv6 Stats site is no longer properly maintained, and the data published there is no longer reliable.

However, the data provided by Facebook also exhibits an odd development, albeit unlike the step change reported by Google. Until March 2022, Dutch IPv6 adoption measured by Facebook was slowly edging up, ultimately passing the 40 per cent mark. The figure then fell abruptly to less than 35 per cent, before continuing to decline towards 30 per cent.

Figure 4: Dutch client-side IPv6 adoption according to Facebook.

New measurement method?

A similar pattern can be seen in the statistics for certain other countries, such as Germany, suggesting that Facebook changed its measurement method in some way at the end of March 2022. However, no such discontinuity is present either in the statistics for most other countries, or in the global statistics. What's more, Google's adoption figures for Germany (and a number of other countries) don't collapse the way that the Dutch figure does.

Figure 5: German client-side IPv6 adoption according to Facebook.

Figure 6: Global client-side IPv6 adoption according to Facebook.

Akamai and APNIC

The IPv6 statistics for the Netherlands published by Akamai and APNIC show adoption levels of 36 and 47 per cent, respectively. Our sense is that those figures are probably more realistic.

Figure 7: Dutch client-side IPv6 adoption according to Akamai.

Figure 8: Dutch IPv6 adoption according to APNIC.

KPN and Ziggo

Because APNIC's data, like Cisco's, does not reflect client-side IPv6 adoption, but adoption on all Dutch networks (ASNs), we are again still looking specifically at KPN and Vodafone-Libertel (Ziggo). Nevertheless, the 3 longitudinal charts published by APNIC show no evidence of discontinuities that might explain the odd patterns reported by Google and Facebook. The Akamai chart therefore now looks like the most useful and the only data source we can currently regard as representative.

Figure 9: IPv6 adoption on Dutch networks according to APNIC.

Figure 10: IPv6 adoption on the KPN network according to APNIC.

Figure 11: IPv6 adoption on the Ziggo network according to APNIC.

Figure 12: IPv6 adoption on Dutch networks according to APNIC.

Figure 13: Dutch IPv6 adoption over time: various data sources show huge divergence. [Source: ISOC Pulse]

Server-side IPv6

On the server side too, we've lost our overview of adoption levels in the last 18 months. There are dozens of websites offering measured data on IPv6 availability. However, nearly all rely on Alexa's 'top 1 million' list of the most visited sites (the Alexa rankings). After Amazon withdrew Alexa back in May 2022, many sources of IPv6 adoption data continued using the most recent Alexa rankings. Over time, therefore, it's inevitable that the data in question has gradually become less closely aligned with the true current top million websites [Tranco, CrUX].

Figure 14: One of the widely consulted sources of IPv6 adoption data that relied on the Alexa rankings. [Source: archive.org/Vyncke.]

Figure 15: Another source of IPv6 adoption data that relied on the Alexa rankings. [Source: DeLong.]

IPv6Matrix: Dutch servers

According to IPv6Matrix, 38 per cent of Dutch servers currently offer an IPv6 port. That figure was calculated by sequentially testing the DNS, web, mail and time servers of the Dutch domain names in the Majestic Million. It does not therefore reflect the IPv6-enabled servers that are most popular with Dutch internet users.

Figure 16: IPv6 adoption on the most popular DNS/web/mail/time servers in the .nl zone. [Source: IPv6Matrix]

SIDN Labs: queries of the .nl zone

Our own statistics show that 28 per cent of queries of the .nl zone are received over IPv6 connections. However, that of course says nothing about the proportion of sites visited by Dutch users that are IPv6-enabled, because the sites most popular with Dutch internet users (like their counterparts in many Western countries) are those of the main US-based (social) media providers.

Figure 17: IPv4/IPv6 traffic to the authoritative name servers for the .nl zone. [Source: SIDN Labs.]

Commercial services

For the compilation of adoption statistics, IPv6 testers perhaps could and should be able to use the rankings published by Semrush and Similarweb: 2 commercial service providers that are both able to break down data regarding the most popular websites by sector and country, and to show the number of visits.

Another potentially useful source is Cloudflare Radar, which produces rankings based on data concerning the 1.1.1.1 public DNS service. Again, these rankings can be broken down by country, but information about the number of requests is not available. Moreover, while rankings that extend beyond the top 100 are available, they are not sorted.

Generally speaking, although there are a few notable exceptions, the most popular websites are also the most likely to support IPv6. The further down the rankings one goes, the lower the adoption level tends to be. [BuiltWith] Hence, the biggest sites account for a disproportionately large percentage of IPv6 sessions and IPv6 traffic. IPv6 support by the major online service providers is therefore very important.

Implications for promotion and policy

The challenges involved in finding and using reliable, up-to-date statistics will only make efforts to boost IPv6 adoption more difficult. Although we know that adoption in the Netherlands lags well behind adoption in neighbouring countries and is more on a par with countries on Europe's periphery, it has become considerably more difficult to reliably quantify the size of the problem.

That makes the task of developing policies to encourage further adoption more challenging. And legislating to mandate IPv6 support is more daunting still. What's more, any such initiatives would depend on effective means of measuring the effects of the measures taken.

The best example is Internet.nl, a portal where users can test whether websites, mail domains and internet connections support standards such as HTTPS, DNSSEC, IPv6, RPKI and SPF/DKIM/DMARC. Although the portal is now used for a wide variety of purposes, it was originally developed to monitor the adoption of modern internet standards by Dutch government bodies. The Internet.nl batch facility is used by the Forum for Standardisation in the compilation of its annual Open Standards Monitoring Report and biannual Information Security Standards Survey. The latter survey is specifically intended to provide data on the adoption of internet security standards for which the Pan-governmental Digital Government Policy Liaison Forum (OBDO) has defined Joint Ambition Statements.

"The tardy adoption of this important, modern internet standard is something we're aware of here at the Platform for Internet Standards as well," says Chair Gerben Klein Baltink. "Although enormous progress has been made within Dutch government circles in relation to both web domains and mail domains, the nation as a whole is lagging behind. For a number of providers, it seems to be a structural issue: the will to migrate to IPv6 is apparently lacking. My advice is go to Internet.nl and test whether your mail and web domains are IPv6 compliant. Then, if your existing service provider can't offer you IPv6 support, switch to one that can."

No problem owner

The lack of IPv6 adoption statistics has also become a structural problem, because (with a few exceptions) no one seems to be particularly worried about it. To borrow the terminology of the business world, the adoption of IPv6 has no problem owner in the Netherlands following disbandment of the IPv6 Task Force in June 2018 and dissolution of the Dutch IPv6 Foundation (Stipv6) in February 2023). And that's something that really should concern The Netherlands Inc, which in 2015 was still able to characterise our digital infrastructure as the nation's third main port, alongside Schiphol airport and Rotterdam seaport.

"In partnership with the Forum for Standardisation and the Platform for Internet Standards, we have been working to promote the large-scale rollout of IPv6 for many years," says SIDN's Chief Technology Officer Loek Bakker. "For example, the financial incentive scheme we operate for registrars has made a significant contribution to growth in the number of IPv6-enabled Dutch DNS, web and mail servers. And we fully intend to remain active in this field, because large-scale implementation of IPv6 is important for the continued growth and future-readiness of the internet. Accurate data on the adoption of IPv6 is a vital source of policy guidance for everyone involved in promoting its use. It's therefore regrettable that the actors that have traditionally campaigned for IPv6 now appear less interested. We are generally sceptical about regulating the use of specific internet technologies. However, given the enormous importance of the internet infrastructure for the Dutch economy, it's now clear that something has to be done."

Having worked in the energy sector for many years, Bakker sees parallels with the Dutch power grid's capacity problems. "The energy sector was too slow to respond to the energy transition and to electrification, with the result that bulk consumers and power suppliers in Brabant and Limburg and in various other parts of the country were unable to realise new connections or expand their capacity. Such problems act as a brake on economic growth. The Netherlands has long been a lead player in the field of internet infrastructure. We really have to guard against squandering our position through neglect and false economisation. We have been warning for years about the Netherlands' sluggish adoption of IPv6, and about the implications both for the accessibility of our internet market and for our investment climate." [1, 2, 3]