Yes — 4b1u.com 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
4b1u.com has 2 IPv6 addresses and answers on every one we tested.
✓ 2606:4700:3032::6815:2a39 answers · 443✓ 2606:4700:3034::ac43:c958 answers · 443
yes
Mail servers (MX) have IPv6
None of the mail servers has an AAAA record.
mail.4b1u.com ✗
no
Nameservers have IPv6
2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
rachel.ns.cloudflare.com ✓sterling.ns.cloudflare.com ✓
yes
HTTPS over IPv6 · not part of the grade yet
Redirects to navynavy83126.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.
https://4b1u.com/ via 2606:4700:3032::6815:2a39 → 302http://navynavy83126.com/ · redirects to navynavy83126.com, which has no IPv6 address
problem
 Which outside scripts, fonts, payments or chat 4b1u.com loads from have no IPv6.
 Load 4b1u.com over IPv6 from up to six other places — a second opinion.

What's keeping 4b1u.com from an A

  1. A redirect leads off IPv6
    Redirects to navynavy83126.com, 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.
  2. Mail servers without IPv6
    mail.4b1u.com has no AAAA record, so mail from IPv6-only servers can't reach it directly. If a provider runs your mail, that's their setting; if you run it, add AAAA records for these hosts.

Check again

4b1u.com  Has IPv6

A (IPv4)104.21.42.57
172.67.201.88
AAAA (IPv6)2606:4700:3032::6815:2a39
2606:4700:3034::ac43:c958

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/jFudz5Alrc · How we measure

Checked 2026-11-12 09:14:31 UTC. Full DNS report: dns.pizza/domain/4b1u.com · Age, certificate and blocklists: how.is/4b1u.com · JSON: /api/v1/4b1u.com