Tracking IPv6 Glue Record Uptake Among Registrars

As the global internet continues its transition toward IPv6, the domain name system infrastructure must evolve in parallel to support native IPv6 connectivity. One key aspect of this transition is the proper handling of glue records—specifically, the inclusion and propagation of AAAA records for name servers—by domain registrars. Glue records are critical components in DNS resolution, serving as authoritative hints that allow recursive resolvers to reach the name servers for a delegated zone without falling into circular dependencies. When those name servers are IPv6-enabled, corresponding IPv6 glue (AAAA) records must be registered and managed at the registry level to ensure seamless resolution. However, uptake of IPv6 glue record support among domain registrars has been inconsistent, creating challenges for domain owners and slowing overall IPv6 adoption.

The importance of glue records in an IPv6 context becomes evident when considering how DNS resolution functions. For any domain whose authoritative name servers lie within its own zone (so-called “in-bailiwick” servers), the resolver requires glue records at the parent zone to locate those servers. Without these glue records, the resolver would be unable to find the address of the name server without querying the domain itself—a logical impossibility without recursion. For domains that have only IPv4 glue (A records), this can result in dual-stack or IPv6-only resolvers falling back to legacy transport, failing to connect, or experiencing significant latency. By contrast, properly maintained IPv6 glue records enable full-resolution capability over native IPv6, enhancing reliability and future-proofing the domain’s availability.

Tracking the uptake of IPv6 glue record support among registrars involves examining registrar capabilities at multiple levels: registrar control panel interfaces, EPP (Extensible Provisioning Protocol) support, backend integration with registry systems, and actual implementation practices for glue record submission. While most modern registrars have long supported A glue records, support for AAAA glue has lagged. Some registrars do not expose UI fields for AAAA records, forcing users to interact via API or customer support. Others accept AAAA glue records but fail to propagate them correctly to the registry, leaving the authoritative data incomplete or inconsistent. These issues are compounded when registrars service multiple TLDs, each with differing registry capabilities, operational policies, and validation logic around glue records.

Empirical studies conducted by DNS research organizations, including ICANN, CENTR, and various academic institutions, have highlighted discrepancies in registrar behavior. For example, a 2022 review of glue record support across more than 100 ICANN-accredited registrars found that fewer than half provided seamless support for adding IPv6 glue records for all TLDs they serviced. In many cases, registrar interfaces only supported A records for glue, and customer support staff were not trained or equipped to handle AAAA glue updates manually. Registrars who do support AAAA glue often restrict that functionality to a small subset of TLDs—typically .com, .net, and certain ccTLDs—leaving newer or less-common TLDs without consistent IPv6 glue support. These inconsistencies contribute to fragmented deployment patterns and discourage domain owners from fully enabling IPv6 on their authoritative infrastructure.

Another dimension to tracking uptake is the measurement of live glue record prevalence. Tools like Zonemaster, DNSViz, and RIPE Atlas probes have been used to scan root zone delegations and identify how many domains include AAAA glue for their name servers. These scans show a steady but slow increase in IPv6 glue adoption. As of 2024, the percentage of delegations in .com and .net with at least one IPv6 glue record remains below 15%, although the growth trajectory is positive. Notably, IPv6 glue record usage is much higher among infrastructure-related domains—such as those operated by large CDNs, cloud providers, and internet exchanges—compared to consumer or small business domains, which are more likely to be hosted on legacy systems with limited registrar support.

Efforts to improve glue record support have come from multiple directions. ICANN has included IPv6 glue compliance in its registrar accreditation agreements and has conducted outreach to raise awareness of its importance. Some registries, such as .SE (Sweden) and .NL (Netherlands), have taken a proactive stance by encouraging or even requiring IPv6 glue for new domain delegations. DNS hosting providers, for their part, are increasingly pressuring registrars to modernize their systems to allow seamless AAAA glue registration, particularly as IPv6 adoption grows in mobile-first markets like India, Brazil, and parts of Africa. Industry working groups, such as those within the DNS Operations, Analysis, and Research Center (DNS-OARC), continue to publish best practices for glue record management and push for harmonization across registrar platforms.

One of the technical challenges registrars face in supporting IPv6 glue stems from historical assumptions embedded in their provisioning systems. Legacy registrar platforms may have hard-coded logic that validates name server addresses based on IPv4 formats, rejecting AAAA inputs as malformed. Others lack robust EPP schema validation for IPv6 or cannot correctly synchronize glue changes across multiple registry partners. These technical debts accumulate over years and are often expensive to remediate, especially when glue record functionality is seen as a low-priority feature in competitive registrar marketplaces. Without market incentives or regulatory pressure, many registrars simply defer upgrading their systems, leaving domain owners in a difficult position.

To address these gaps, domain owners who require IPv6 glue support are increasingly seeking out registrars that advertise IPv6 readiness as part of their service offerings. Some managed DNS providers also offer domain registration services specifically tailored for IPv6 compliance, bundling glue record management with authoritative DNS hosting. In cases where registrars are not responsive to glue record requests, domain owners sometimes resort to transferring their domain to a more capable registrar—a disruptive process that introduces downtime risk and administrative overhead but remains one of the few mechanisms available to force compliance.

In summary, tracking IPv6 glue record uptake among registrars reveals a mixed landscape of partial support, operational inconsistency, and slow progress. While technical standards fully support AAAA glue, and while the necessity for such records is well understood in the IPv6 transition, the registrar ecosystem has not uniformly implemented these capabilities. As a result, many domains remain IPv6-incomplete, undermining the reliability and efficiency of DNS resolution for a growing portion of the internet. Continued measurement, transparency, and community pressure are essential to accelerate uptake and ensure that the DNS infrastructure is fully prepared for an IPv6-dominant future. The successful propagation of IPv6 glue records is not just a technical checkbox—it is a prerequisite for resilient, future-ready domain name services in a rapidly evolving global network.

As the global internet continues its transition toward IPv6, the domain name system infrastructure must evolve in parallel to support native IPv6 connectivity. One key aspect of this transition is the proper handling of glue records—specifically, the inclusion and propagation of AAAA records for name servers—by domain registrars. Glue records are critical components in DNS…