Yes — cognicloud.dev has IPv6.

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

IPv6 readiness

Works over IPv6, with one gap: its mail servers lack IPv6.

Website over IPv6 cognicloud.dev has an AAAA record and answers on it. ✓ 2001:41d0:301:5::29 answers · 443	yes
www over IPv6 www.cognicloud.dev has an AAAA record and answers on it. ✓ 2001:41d0:301:5::29 answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. mx1.mail.ovh.net ✗mx2.mail.ovh.net ✗mx3.mail.ovh.net ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns103.ovh.net ✓dns103.ovh.net ✓	yes

HTTPS over IPv6 · not part of the grade yet
The certificate served over IPv6 at 2001:41d0:301:5::29 isn't valid for cognicloud.dev: ERR_TLS_CERT_ALTNAME_INVALID.

https://cognicloud.dev/ via 2001:41d0:301:5::29 · ERR_TLS_CERT_ALTNAME_INVALID

problem

What's keeping cognicloud.dev from an A

The certificate served over IPv6 is wrong
The certificate served over IPv6 at 2001:41d0:301:5::29 isn't valid for cognicloud.dev: ERR_TLS_CERT_ALTNAME_INVALID. Often the IPv6 address points at a different server (or an old one) than IPv4 does. Make sure 2001:41d0:301:5::29 serves the same certificate as your IPv4 address.
Mail servers without IPv6
mx1.mail.ovh.net, mx2.mail.ovh.net, mx3.mail.ovh.net have no AAAA record, so mail from IPv6-only servers can't reach them directly. If a provider runs your mail, that's their setting; if you run it, add AAAA records for these hosts.

Check again

cognicloud.dev Has IPv6

A (IPv4)	40.116.70.6
AAAA (IPv6)	2001:41d0:301:5::29

www.cognicloud.dev Has IPv6

A (IPv4)	40.116.70.6
AAAA (IPv6)	2001:41d0:301:5::29

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: cognicloud.dev
Measured 2026-11-04 03:35:53 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    40.116.70.6
AAAA (IPv6): 2001:41d0:301:5::29
www AAAA:    2001:41d0:301:5::29

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: cognicloud.dev has an AAAA record and answers on it.
    2001:41d0:301:5::29: answers (TCP 443)
- www over IPv6: www.cognicloud.dev has an AAAA record and answers on it.
    2001:41d0:301:5::29: answers (TCP 443)
- Mail servers (MX) have IPv6: None of the mail servers has an AAAA record.
- Nameservers have IPv6: 2 of 2 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 2001:41d0:301:5::29 isn't valid for cognicloud.dev: ERR_TLS_CERT_ALTNAME_INVALID.
    https://cognicloud.dev/ via 2001:41d0:301:5::29, certificate: ERR_TLS_CERT_ALTNAME_INVALID
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/T7SiEUiDus

Permanent link: aaaa.bot/r/T7SiEUiDus · How we measure

Checked 2026-11-04 03:35:53 UTC. Full DNS report: dns.pizza/domain/cognicloud.dev · Age, certificate and blocklists: how.is/cognicloud.dev · JSON: /api/v1/cognicloud.dev