Yes — spamhaus.org has IPv6.

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

IPv6 readiness

Works over IPv6, with gaps: www doesn't fully work over IPv6; its mail servers lack IPv6.

Website over IPv6 spamhaus.org has an AAAA record and answers on it. ✓ 2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4 answers · 443	yes
www over IPv6 www.spamhaus.org has no AAAA record.	no
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. mx.spamhaus.org ✗bmx.spamhaus.org ✗	no
Nameservers have IPv6 6 of 6 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. musashi.spamhaus.com ✓musashi.spamhaus.net ✓musashi.spamhaus.org ✓hideyoshi.spamhaus.com ✓hideyoshi.spamhaus.net ✓hideyoshi.spamhaus.org ✓	yes

HTTPS over IPv6 · not part of the grade yet
Redirects to www.spamhaus.org, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.

https://spamhaus.org/ via 2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4 → 301https://www.spamhaus.org/ · redirects to www.spamhaus.org, which has no IPv6 address

problem

What's keeping spamhaus.org from an A

www.spamhaus.org is an alias of www.spamhaus.org.cdn.cloudflare.net, which has no IPv6
www.spamhaus.org is a CNAME, so it can't also have its own AAAA record. Ask whoever runs www.spamhaus.org.cdn.cloudflare.net to enable IPv6 there — or replace the alias with the A and AAAA records they give you. Why some hosts don't offer IPv6
A redirect leads off IPv6
Redirects to www.spamhaus.org, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all. Give the redirect target IPv6 too, or redirect somewhere that has it.
Mail servers without IPv6
mx.spamhaus.org, bmx.spamhaus.org 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

spamhaus.org Has IPv6

A (IPv4)	3.126.246.180
AAAA (IPv6)	2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4

www.spamhaus.org IPv4 only

Alias of	www.spamhaus.org.cdn.cloudflare.net
A (IPv4)	104.16.198.238 104.16.199.238
AAAA (IPv6)	none

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: spamhaus.org
Measured 2026-10-31 06:04:39 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    3.126.246.180
AAAA (IPv6): 2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4
www AAAA:    none

Readiness grade C: Works over IPv6, with gaps: www doesn't fully work over IPv6; its mail servers lack IPv6.
- Website over IPv6: spamhaus.org has an AAAA record and answers on it.
    2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4: answers (TCP 443)
- www over IPv6: www.spamhaus.org has no AAAA record.
- Mail servers (MX) have IPv6: None of the mail servers has an AAAA record.
- Nameservers have IPv6: 6 of 6 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): Redirects to www.spamhaus.org, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.
    https://spamhaus.org/ via 2a05:d014:1bf:db01:bbc8:62e2:948e:6bf4 -> HTTP 301, certificate: valid
    https://www.spamhaus.org/ (redirects to www.spamhaus.org, which has no IPv6 address)
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/NLEkcSYZty

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

Checked 2026-10-31 06:04:39 UTC — one of the top 1,000 sites, re-checked weekly. Re-check now. Full DNS report: dns.pizza/domain/spamhaus.org · JSON: /api/v1/spamhaus.org