usefulweb.site IPv6 Readiness Explorer

Internet infrastructure explorers

IPv6 Readiness Explorer

Is a domain reachable over IPv6? Web, DNS and mail checks, address classes and a scored report.

Pasted mode: {domain, hosts:[{name, ipv4, ipv6}], nameservers:[…], mx:[{name, priority, ipv4, ipv6}], connect?:[{host, address, ok, code}]}

Try an example: Pasted record set: partial IPv6

How it works

Checks AAAA records for a domain and its www host, IPv6 addresses of its name servers and mail servers, classifies every IPv6 address (global unicast vs ULA, link-local, documentation, 6to4, Teredo, NAT64 …), optionally opens a TCP connection to port 443 over IPv6, and turns it into a score with every check explained.

  • Resolves A and AAAA for the domain and www.<domain>, the NS host names and the MX host names (up to 10) with this server's resolver.
  • Every IPv6 address is classified against the IANA IPv6 special-purpose registry: only global unicast (2000::/3 minus special blocks) is reachable from the internet.
  • Score (points, n/a checks are excluded from the maximum): apex AAAA 25, www AAAA 15, any name server with IPv6 20, all name servers with IPv6 10, MX with IPv6 15 (pro rata), no special-purpose addresses 5, TCP 443 over IPv6 10. Grade A ≥ 90, B ≥ 75, C ≥ 50, D ≥ 25.
  • Connect test: up to 3 global AAAA addresses of the domain/www, TCP handshake on port 443 with a 5 s timeout. If this server itself has no IPv6 route (ENETUNREACH/EADDRNOTAVAIL), the test is reported as not possible instead of counted as a failure.

For scripts and AI agents

  • JSON API: POST https://ipv6readinessexplorer.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://ipv6readinessexplorer.usefulweb.site/mcp · tool name ipv6_readiness_explorer
Example request
curl -s -X POST https://ipv6readinessexplorer.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{…see OpenAPI examples…}'

Related tools

  • Global DNS Explorer – Ask every authoritative name server and public resolvers: records, propagation, DNSSEC, mistakes.
  • DNS + Certificate Explorer – DNS records, e-mail security, CAA, live TLS certificate and CT history for a domain.
Feedback