Welcome to v6only-resolver.measurement.network

This service can scan your domain for misconfigurations regarding IPv6 DNS resolution.


Q: What does this do?
A: This service scans domains for broken IPv6 configuration.

Q: Can I also test things manually?
A: Sure! We run an open resolver on this system that only supports IPv6! You can query it with:

    dig @v6only-resolver.measurement.network
    dig @2a06:d1c0:dead:2::173
    dig @

Q: Why is my scan taking so long?
A: For the best possible results, we scan the entire authoritative server structure related to your domain. This can take a while, especially if some servers are unresponsive.

Q: Why not simply check for AAAA records?
A: For a true IPv6-only scenario, it is not enough if AAAA records are present. As of today, many issues are hidden by dual-stack resolution.

Q: What types of misconfigurations are there?
A: There are 4 basic types of misconfigurations that cause broken IPv6 resolution:
- Missing AAAA for domain: If the domain does not have an AAAA record, it is not reachable via IPv6.
- Missing AAAA for name server: If the name server name has no associated AAAA record, it can not be queried.
- Missing Glue: If a name server is in-bailiwick, parent name servers must serve AAAA glue records
- Missing AAAA for in-bailiwick NS: If a name server is in-bailiwick, it must still have a AAAA record in its zone for resolvers that validate the delegation path.
Additionally, this leads to the following issues
- Parent zone not resolving: If the parent of a zone does not resolve, the zone itself is also unresolvable
- Name server zone not resolving: If the zone of a name servers' name does not resolve, the name server is not usable for IPv6-only resolution.

Q: Does a misconfiguration mean my site is not reachable via IPv6?
A: Right now? Not necessarily, as dual-stack resolution hides many problems. In the future? Yes, unless the issues are addressed.

Q: So, authoritative DNS for IPv6 is really spotty; So we better stick with legacy IP, right?
A: No.

Q: This all sounds really interesting. Where can i learn more?
A: Here: Streibelt et al., 'How Ready Is DNS for an IPv6-Only World?', Passive and Active Measurement Conference, 2023.

Q: Who runs this service?
A: This site is operated by Tobias Fiebig & has been implemented by Florian Steurer, Campus E14, 66123 Saarbr├╝cken, Germany, Email: contact@as59645.net.

Q: Do you have a privacy policy?
A: Yeah. Here: There are no cookies, and we only process data to provide this service (deliver this page, keep the service running, and resolve your DNS requests). i.e., to provide this service (Art. 13 DSGVO). We store received requests (IP, Resource, UserAgent, queried Domain) and resolution errors in the daemon logs for up to two weeks to be able to analyze issues with the service. You can request deletion, correction, or a copy of your data (as long as it is not already provided via the site) by writing an email to: contact@as59645.net