IPv6 and CTV: The Measurement Challenge From the Fastest-Growing Ad Channel
Connected TV advertising will reach $26.6 billion in the U.S. in 2025 according to IAB, making it the fastest-growing segment in digital advertising. It's also becoming the first channel to fully confront what IPv6 adoption means for measurement at scale.
The challenges CTV advertisers are facing, like address rotation breaking frequency caps, privacy extensions disrupting tracking, geo-targeting struggling with vast IPv6 ranges, aren't unique to streaming. They're a preview of what's coming for all digital advertising as IPv6 becomes the dominant protocol.
With IPv6 now being the primary means that users connect to the internet (86% in France, 75% in Germany, 52% in the U.S.), the measurement infrastructure built for IPv4's stability is producing increasingly unreliable results across programmatic display, mobile advertising, video campaigns, and CTV.
Current IPv6 adoption by country:
Source: Google IPv6 Statistics, November 2025
IPv6 will affect your measurement, and you'll want to be ready.
What Makes IPv6 Different And Why It Breaks Measurement
When IPv4 finally ran out of space in 2011, IPv6 answered with scale: 340 undecillion (3.4 × 10³⁸) possible addresses, enough to assign billions of unique identifiers to every person on earth.
Yet that scale also changed the internet’s structure: with so many addresses, only a minute fraction are actually allocated or active, making it impossible to “scan” the IPv6 internet the way we did with IPv4.
More importantly, IPv6 didn’t just expand capacity; it changed behavior. Its privacy-first architecture makes the network far more dynamic, creating new challenges for anyone trying to measure, target, or attribute digital traffic accurately.
Read our comparison of IPv4 and IPv6.
Address Rotation: Short-Lived Device Identities
Devices don’t keep the same IPv6 address for long. According to RFC 4941 and its 2021 update RFC 8981, modern devices operating systems (from smartphones to smart TVs) use privacy extensions, a mechanism that creates temporary, randomly generated IPv6 addresses and replaces them every 24–72 hours (sometimes even more frequently).
The goal is privacy: early versions of IPv6 embedded a device’s hardware ID (the MAC address) directly in the IP, making long-term tracking trivial. Privacy extensions fixed that by introducing randomization, but in doing so, they also broke the persistence advertisers and analytics rely on.
The same device can now appear under several different addresses within a single week, making it nearly impossible to link impressions, sessions, or behaviors over time.
Prefix Reassignment: Households That “Move” Without Moving
ISPs take this privacy principle a step further. Many residential networks periodically rotate the customer’s entire prefix (/56 or /48) effectively reassigning each household a new IPv6 block every day. Studies including Follow the Scent, One Bad Apple Can Spoil Your IPv6 Privacy, and the APNIC Blog confirm that daily prefix cycling is now common among large broadband providers.
Where IPv4 offered relative stability, IPv6 is fluid by design. For digital advertisers across all channels, this means one fundamental shift: you can't assume. You have to measure.
Why Connected TV Hit the Wall First
CTV advertising is the first channel where the challenges with IPv6 measurement became impossible to ignore.
Why CTV exposed it:
- CTVs adopted IPv6 earlier than most digital channels.
- Household-level targeting makes measurement errors immediately visible.
- Brand advertisers expect precise reach and frequency controls, the very things IPv6 disrupts.
The Cascading Effects Hitting CTV Campaigns Now
Under IPv6, the same household can appear as dozens of different “users” within a week. An advertiser may serve ten impressions to what looks like ten different homes when it’s actually one family whose addresses change every 48 hours.
Frequency capping fails. Reach calculations inflate. Attribution models break. And because IPv6 ranges are large and frequently reassigned by ISPs, geo-targeting also loses precision, the same network block can represent different households over time.
While individual IPv6 addresses can be extremely specific and often tied to a single device, that precision doesn’t last. Privacy extensions and dynamic prefix delegation mean those identifiers rotate constantly, turning what should be a strength into a measurement challenge.
These same problems are coming for every advertising channel. Programmatic display, mobile advertising, and video platforms across the web will see the same phantom audience inflation and attribution drift.
CTV advertisers are just the first to feel it at scale.
IPv6 Aware Campaign Lifecycle Across Channels
As IPv6 becomes the dominant protocol, advertising platforms across all channels need IPv6-aware measurement:
Making IPv6 Measurable for All Advertising
Accurately mapping the IPv6 internet for advertising takes more than legacy methodologies. It requires active measurement, continuous validation, and research-grade expertise applied to the challenges adtech platforms face every day: attribution, targeting, and fraud prevention.
IPv6 Requires a New Measurement Model
IPv6 networks behave differently from IPv4 in nearly every way, from how addresses are allocated to how ISPs design privacy and naming systems. Legacy IPv4 heuristics simply don’t hold up.
That’s why IPinfo built a new measurement model, one designed specifically for IPv6’s fluid and privacy-centric architecture, grounded in research and active validation rather than static lookups. Most IP data providers simply “bolt on” IPv6 to IPv4-based systems, resulting in patchy coverage and low accuracy.
IPinfo took a different path: we built IPv6 measurement from the ground up, guided by empirical validation and peer-reviewed research.
IPv6 Coverage: Knowing What’s Really Out There
Even identifying which IPv6 addresses exist is a challenge. Out of 340 undecillion (3.4 × 10³⁸) possible addresses, only a tiny fraction are actually allocated and fewer still are active.
Traditional mapping methods don’t scale to that size; blind scanning hits mostly empty space. That’s why accurate IPv6 mapping requires blending multiple data sources; no single feed can reveal the full picture:
IPv6 coverage means identifying which prefixes are allocated, announced, and active and keeping that intelligence current as networks evolve.
Research-Grade IPv6 Expertise
Before joining IPinfo, our Head of Research, Oliver Gasser, led IPv6 measurement research at TU Munich (Technical University of Munich) and the Max Planck Institute for Informatics.
He co-authored several of the foundational academic papers that built modern IPv6 measurement:
- “Clusters in the Expanse” (IMC 2018). Introduced the first systematic approach to build and validate large-scale IPv6 address hitlists.
- “Rusty Clusters?” (IMC 2022). Refined the methodology, filtering aliased prefixes and improving address diversity and quality.
- “Target Acquired?” (TMA 2023). Benchmarked all major algorithms for discovering active IPv6 addresses and quantified their bias, coverage, and responsiveness.
These studies directly led to the public IPv6 Hitlist Service at https://ipv6hitlist.github.io, now the global benchmark dataset for understanding IPv6 topology and responsiveness.
Today, that same methodology powers IPinfo’s datasets.
By combining the scientific rigor of the IPv6 Hitlist with ProbeNet’s global scale, we continuously validate, classify, and geolocate IPv6 addresses using peer-reviewed techniques trusted by the research community.
Our IPv6 Infrastructure and Measurement Scale
Counting IPs isn’t the right measure of IPv6 coverage: every provider can list all allocated addresses, since that data comes from public WHOIS registries. What matters is evidence: how many of those addresses have been actively measured, verified, or observed in use.
At IPinfo, we combine registry completeness with large-scale, evidence-based validation through ProbeNet and the IPv6 Hitlist. Every week, we:
- Measure 3.6 billion IPv6 addresses across the active internet
- Obtain latency (RTT) measurements for ~325 million IPv6 addresses
- Identify 224 million IPv6 routers through topology and alias resolution
For comparison, IPv4 coverage includes 3.1B measured addresses, ~484M with RTT data, and 5.4M routers. IPv6 router counts appear much higher than IPv4 (224 M vs 5.4 M) because IPv6 devices are directly addressable and visible in traceroute measurements. IPv6 exposes much more of the network’s inner structure. Because IPv6 depends on ICMP for basic operation and lacks the NAT layers that hide IPv4 devices so traceroutes reach deeper, revealing many more router interfaces. It’s not that the internet suddenly has more hardware; IPv6 simply makes it visible.
Unlike providers who simply catalog IPv6 allocations from public registries, IPinfo continuously measures and validates active IPv6 networks, combining registry coverage with large-scale measurement evidence. This approach makes IPinfo one of the few companies providing IPv6 data grounded in real, observable internet behavior, not just static records.
Full IPv6 Coverage, Verified Daily
IPinfo’s datasets cover all allocated IPv4 and IPv6 space, verified through registry data and active measurement. When new allocations occur or ranges transfer, updates propagate across our datasets within 24 hours.
ProbeNet, our internet measurement platform, performs continuous latency sampling, traceroutes, and network validation from over 1,200 points of presence in 140+ countries.
Whether you're buying CTV, mobile, display, or video, newly allocated residential IPv6 blocks are classified correctly from day one, not months later when legacy databases finally catch up.
These measurements ground our data in empirical reality. For advertising across all channels, this means:
- Distinguishing residential traffic from CDN infrastructure
- Providing geo-resolution that reflects where IPs actually are
- Detecting network patterns critical for fraud prevention
The Path Forward
IPv6 is already the majority protocol in many markets, and that percentage grows daily. For businesses that depend on IP intelligence, the choice is clear: Adapt to IPv6's fluid, privacy-conscious architecture with measurement-based data or watch accuracy degrade as IPv4 heuristics become increasingly irrelevant.
IPinfo’s investment in IPv6 measurement, led by Oliver Gasser, a pioneer in global IPv6 research, ensures our data stays aligned with the most advanced methodologies in the field. We've built our infrastructure around a simple principle: the only trustworthy IPv6 data comes from active measurement combined with research-grade methodology. That means:
- 100% coverage of IPv6 allocated space
- Daily updates as ranges change hands
- Last-change timestamp for geolocation and ASN
- Network-type classification to separate ISP from infrastructure
- POI identification (airport, airplane, hotel and more) for precise targeting
- Anonymous IPs detection
- ProbeNet validation across 1,200+ global points of presence
- Peer-reviewed research methodology in production
Take Action
Is IPv6 affecting your measurement accuracy across channels? Are you confident in your network classification and geolocation for IPv6 traffic?
Want to see how IPv6 impacts your data? Reach out to learn how IPinfo's measurement-based approach can bring clarity to your IPv6 traffic.
Acknowledgments
This article was written with generous input and technical guidance from Dr. Maxime Mouchet and Dr. Oliver Gasser, whose research and engineering work continue to shape how IPinfo measures and understands the modern internet. I’ve learned a great deal through this process about how the internet actually works beneath the surface from routing and measurement to the nuances of IPv6 adoption and visibility.
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About the author
As the product marketing manager, Fernanda helps customers better understand how IPinfo products can serve their needs.