Yes — rubiconproject.com has IPv6.

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

B
IPv6 readiness
Works over IPv6, with one gap: www doesn't fully work over IPv6.
Website over IPv6
rubiconproject.com has 4 IPv6 addresses and answers on every one we tested (4 more not tested).
✓ 2600:9000:286a:ea00:19:133b:2800:93a1 answers · 443✓ 2600:9000:286a:c600:19:133b:2800:93a1 answers · 443✓ 2600:9000:286a:7200:19:133b:2800:93a1 answers · 443✓ 2600:9000:286a:9800:19:133b:2800:93a1 answers · 443– 2600:9000:286a:2600:19:133b:2800:93a1 not tested– 2600:9000:286a:fc00:19:133b:2800:93a1 not tested– 2600:9000:286a:be00:19:133b:2800:93a1 not tested– 2600:9000:286a:5a00:19:133b:2800:93a1 not tested
yes
www over IPv6
www.rubiconproject.com has no AAAA record.		no
Mail servers (MX) have IPv6
Every mail server has an AAAA record.
aspmx.l.google.com ✓aspmx2.googlemail.com ✓aspmx3.googlemail.com ✓alt1.aspmx.l.google.com ✓alt2.aspmx.l.google.com ✓
yes
Nameservers have IPv6
4 of 4 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
ns-1150.awsdns-15.org ✓ns-1722.awsdns-23.co.uk ✓ns-483.awsdns-60.com ✓ns-644.awsdns-16.net ✓
yes
HTTPS over IPv6 · not part of the grade yet
Redirects to www.rubiconproject.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.
https://rubiconproject.com/ via 2600:9000:286a:ea00:19:133b:2800:93a1 → 301https://www.rubiconproject.com/ · redirects to www.rubiconproject.com, which has no IPv6 address
problem
 Load rubiconproject.com over IPv6 from up to six other places — a second opinion.

What's keeping rubiconproject.com from an A

  1. www.rubiconproject.com is an alias of 1y0y7y9io391.wpeproxy.com, which has no IPv6
    www.rubiconproject.com is a CNAME, so it can't also have its own AAAA record. Ask whoever runs 1y0y7y9io391.wpeproxy.com to enable IPv6 there — or replace the alias with the A and AAAA records they give you. Why some hosts don't offer IPv6
  2. A redirect leads off IPv6
    Redirects to www.rubiconproject.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.

Check again

rubiconproject.com  Has IPv6

A (IPv4)3.170.3.15
3.170.3.81
3.170.3.28
3.170.3.16
AAAA (IPv6)2600:9000:286a:ea00:19:133b:2800:93a1
2600:9000:286a:c600:19:133b:2800:93a1
2600:9000:286a:7200:19:133b:2800:93a1
2600:9000:286a:9800:19:133b:2800:93a1
2600:9000:286a:2600:19:133b:2800:93a1
2600:9000:286a:fc00:19:133b:2800:93a1
2600:9000:286a:be00:19:133b:2800:93a1
2600:9000:286a:5a00:19:133b:2800:93a1

www.rubiconproject.com  IPv4 only

Alias of1y0y7y9io391.wpeproxy.com
A (IPv4)141.193.213.20
141.193.213.21
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

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

Checked 2026-10-31 13:51:22 UTC. Full DNS report: dns.pizza/domain/rubiconproject.com · JSON: /api/v1/rubiconproject.com