Has both IPv4 (A) and IPv6 (AAAA) addresses.
Measured 2026-11-04 13:03 UTC. We reuse a result for up to a week, so we aren't testing the same site over and over. Check cra.cz now
| Website over IPv6 cra.cz has an AAAA record and answers on it. ✓ 2a02:a40:200:3955::78 answers · 443 | yes |
| www over IPv6 www.cra.cz has an AAAA record and answers on it. ✓ 2a02:a40:200:3955::78 answers · 443 | yes |
| Mail servers (MX) have IPv6 Every mail server has an AAAA record. cra-cz.mail.protection.outlook.com ✓ | yes |
| Nameservers have IPv6 3 of 3 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns.bluetone.cz ✓ns1.bluetone.cz ✓ns2.bluetone.cz ✓ | yes |
First measured 2026-11-04; last confirmed 2026-11-04.
| HTTPS over IPv6 · not part of the grade yet Loads over IPv6 with a valid certificate after 1 redirect: HTTP 403. https://cra.cz/ via 2a02:a40:200:3955::78 → 301https://www.cra.cz/ via 2a02:a40:200:3955::78 → 403 | works |
cra.cz Has IPv6
| A (IPv4) | 82.99.159.78 |
|---|---|
| AAAA (IPv6) | 2a02:a40:200:3955::78 |
www.cra.cz Has IPv6
| A (IPv4) | 82.99.159.78 |
|---|---|
| AAAA (IPv6) | 2a02:a40:200:3955::78 |
Browsers on dual-stack networks will usually pick IPv6 here (the "Happy Eyeballs" algorithm races both and prefers v6).
Permanent link: aaaa.bot/r/duiigl_-Nd · How we measure
Checked 2026-11-04 13:03:02 UTC. Full DNS report: dns.pizza/domain/cra.cz · Age, certificate and blocklists: how.is/cra.cz · JSON: /api/v1/cra.cz