Yes — clevelandclinic.org has IPv6.

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

Measured 2026-10-31 23:31 UTC. We reuse a result for up to a week, so we aren't testing the same site over and over. Check clevelandclinic.org now

IPv6 readiness

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

Website over IPv6 clevelandclinic.org has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:4407::6812:20d8 answers · 443✓ 2a06:98c1:3103::ac40:9b28 answers · 443	yes
www over IPv6 www.clevelandclinic.org has 2 IPv6 addresses and answers on every one we tested. ✓ 2a06:98c1:3101::6812:25c5 answers · 443✓ 2606:4700:4406::ac40:963b answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. us-smtp-inbound-1.mimecast.com ✗us-smtp-inbound-2.mimecast.com ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. bob.ns.cloudflare.com ✓etta.ns.cloudflare.com ✓	yes

First measured 2026-10-31; last confirmed 2026-10-31.

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate after 2 redirects: HTTP 200.

https://clevelandclinic.org/ via 2606:4700:4407::6812:20d8 → 302https://www.clevelandclinic.org/ via 2a06:98c1:3101::6812:25c5 → 302https://my.clevelandclinic.org/ via 2a06:98c1:3103::ac40:9b28 → 200

works

What's keeping clevelandclinic.org from an A

Mail servers without IPv6
us-smtp-inbound-1.mimecast.com, us-smtp-inbound-2.mimecast.com 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

clevelandclinic.org Has IPv6

A (IPv4)	104.18.32.216 172.64.155.40
AAAA (IPv6)	2606:4700:4407::6812:20d8 2a06:98c1:3103::ac40:9b28

www.clevelandclinic.org Has IPv6

A (IPv4)	172.64.150.59 104.18.37.197
AAAA (IPv6)	2a06:98c1:3101::6812:25c5 2606:4700:4406::ac40:963b

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: clevelandclinic.org
Measured 2026-10-31 23:31:51 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.18.32.216, 172.64.155.40
AAAA (IPv6): 2606:4700:4407::6812:20d8, 2a06:98c1:3103::ac40:9b28
www AAAA:    2a06:98c1:3101::6812:25c5, 2606:4700:4406::ac40:963b

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: clevelandclinic.org has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:4407::6812:20d8: answers (TCP 443)
    2a06:98c1:3103::ac40:9b28: answers (TCP 443)
- www over IPv6: www.clevelandclinic.org has 2 IPv6 addresses and answers on every one we tested.
    2a06:98c1:3101::6812:25c5: answers (TCP 443)
    2606:4700:4406::ac40:963b: 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): Loads over IPv6 with a valid certificate after 2 redirects: HTTP 200.
    https://clevelandclinic.org/ via 2606:4700:4407::6812:20d8 -> HTTP 302, certificate: valid
    https://www.clevelandclinic.org/ via 2a06:98c1:3101::6812:25c5 -> HTTP 302, certificate: valid
    https://my.clevelandclinic.org/ via 2a06:98c1:3103::ac40:9b28 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/gOA2nTSYBS

Permanent link: aaaa.bot/r/gOA2nTSYBS · How we measure

Checked 2026-10-31 23:31:51 UTC. Full DNS report: dns.pizza/domain/clevelandclinic.org · JSON: /api/v1/clevelandclinic.org