Yes — seibl.org has IPv6.

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

B
IPv6 readiness
Works over IPv6, with one gap: its mail servers lack IPv6.
Website over IPv6
seibl.org has 2 IPv6 addresses and answers on every one we tested.
✓ 2606:4700:3032::ac43:adda answers · 443✓ 2606:4700:3032::6815:280d answers · 443
yes
Mail servers (MX) have IPv6
None of the mail servers has an AAAA record.
mx01.mail.icloud.com ✗mx02.mail.icloud.com ✗
no
Nameservers have IPv6
2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
lady.ns.cloudflare.com ✓neil.ns.cloudflare.com ✓
yes
HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 403.
https://seibl.org/ via 2606:4700:3032::ac43:adda → 403
works
 Which outside scripts, fonts, payments or chat seibl.org loads from have no IPv6.
 Load seibl.org over IPv6 from up to six other places — a second opinion.

What's keeping seibl.org from an A

  1. Mail servers without IPv6
    mx01.mail.icloud.com, mx02.mail.icloud.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

seibl.org  Has IPv6

A (IPv4)172.67.173.218
104.21.40.13
AAAA (IPv6)2606:4700:3032::ac43:adda
2606:4700:3032::6815:280d

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

 Permanent link: aaaa.bot/r/HNfuYMTy1y · How we measure

Checked 2026-11-13 21:51:17 UTC. Full DNS report: dns.pizza/domain/seibl.org · Age, certificate and blocklists: how.is/seibl.org · JSON: /api/v1/seibl.org