Yes — pozarne-bezpecnostni-reseni-staveb.online has IPv6.

Has both IPv4 (A) and IPv6 (AAAA) addresses.

This is a saved measurement from 2026-11-02 06:47 UTC. Check pozarne-bezpecnostni-reseni-staveb.online live now

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 pozarne-bezpecnostni-reseni-staveb.online has an AAAA record and answers on it. ✓ 2a00:4b40:aaaa:2005::6 answers · 443	yes
www over IPv6 www.pozarne-bezpecnostni-reseni-staveb.online has an AAAA record and answers on it. ✓ 2a00:4b40:aaaa:2005::6 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. mx10.active24.cz ✓mx20.active24.cz ✓	yes
Nameservers have IPv6 3 of 3 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns1.websupport.cz ✓ns2.websupport.cz ✓ns3.websupport.eu ✓	yes

HTTPS over IPv6 · not part of the grade yet
The certificate served over IPv6 at 2a00:4b40:aaaa:2005::6 isn't valid for pozarne-bezpecnostni-reseni-staveb.online: ERR_TLS_CERT_ALTNAME_INVALID.

https://pozarne-bezpecnostni-reseni-staveb.online/ via 2a00:4b40:aaaa:2005::6 · ERR_TLS_CERT_ALTNAME_INVALID

problem

Nothing keeping you from an A

The certificate served over IPv6 is wrong
The certificate served over IPv6 at 2a00:4b40:aaaa:2005::6 isn't valid for pozarne-bezpecnostni-reseni-staveb.online: ERR_TLS_CERT_ALTNAME_INVALID. Often the IPv6 address points at a different server (or an old one) than IPv4 does. Make sure 2a00:4b40:aaaa:2005::6 serves the same certificate as your IPv4 address.

Check again

pozarne-bezpecnostni-reseni-staveb.online Has IPv6

A (IPv4)	37.9.175.163
AAAA (IPv6)	2a00:4b40:aaaa:2005::6

www.pozarne-bezpecnostni-reseni-staveb.online Has IPv6

A (IPv4)	37.9.175.163
AAAA (IPv6)	2a00:4b40:aaaa:2005::6

Browsers on dual-stack networks will usually pick IPv6 here (the "Happy Eyeballs" algorithm races both and prefers v6).

Copy the evidence — a citation-ready record of this measurement

IPv6 measurement: pozarne-bezpecnostni-reseni-staveb.online
Measured 2026-11-02 06:47:42 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    37.9.175.163
AAAA (IPv6): 2a00:4b40:aaaa:2005::6
www AAAA:    2a00:4b40:aaaa:2005::6

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: pozarne-bezpecnostni-reseni-staveb.online has an AAAA record and answers on it.
    2a00:4b40:aaaa:2005::6: answers (TCP 443)
- www over IPv6: www.pozarne-bezpecnostni-reseni-staveb.online has an AAAA record and answers on it.
    2a00:4b40:aaaa:2005::6: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server has an AAAA record.
- Nameservers have IPv6: 3 of 3 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.

Reachability = a TCP connection opened on port 443 (or 80).

HTTPS over IPv6 (not graded): The certificate served over IPv6 at 2a00:4b40:aaaa:2005::6 isn't valid for pozarne-bezpecnostni-reseni-staveb.online: ERR_TLS_CERT_ALTNAME_INVALID.
    https://pozarne-bezpecnostni-reseni-staveb.online/ via 2a00:4b40:aaaa:2005::6, certificate: ERR_TLS_CERT_ALTNAME_INVALID
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/2sJWgpzGXb

Permanent link: aaaa.bot/r/2sJWgpzGXb · How we measure

Checked 2026-11-02 06:47:42 UTC. Full DNS report: dns.pizza/domain/pozarne-bezpecnostni-reseni-staveb.online · JSON: /api/v1/pozarne-bezpecnostni-reseni-staveb.online