Yes — astronomy.ltd 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
astronomy.ltd has 2 IPv6 addresses and answers on every one we tested.
✓ 2606:4700:3036::6815:4eba answers · 443✓ 2606:4700:3037::ac43:a857 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.
damian.ns.cloudflare.com ✓zariyah.ns.cloudflare.com ✓
yes
HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 403.
https://astronomy.ltd/ via 2606:4700:3036::6815:4eba → 403
works
 Which outside scripts, fonts, payments or chat astronomy.ltd loads from have no IPv6.
 Load astronomy.ltd over IPv6 from up to six other places — a second opinion.

What's keeping astronomy.ltd 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

astronomy.ltd  Has IPv6

A (IPv4)104.21.78.186
172.67.168.87
AAAA (IPv6)2606:4700:3036::6815:4eba
2606:4700:3037::ac43:a857

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/Ps_DUBhJWd · How we measure

Checked 2026-11-10 03:24:58 UTC. Full DNS report: dns.pizza/domain/astronomy.ltd · Age, certificate and blocklists: how.is/astronomy.ltd · JSON: /api/v1/astronomy.ltd