Yes — auth0.com has IPv6.

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

IPv6 readiness

Works over IPv6, with one gap: its mail servers lack IPv6.

Website over IPv6 auth0.com has 2 IPv6 addresses and answers on every one we tested. ✓ 2a06:98c1:310b::6812:2512 answers · 443✓ 2606:4700:4407::ac40:96ee answers · 443	yes
www over IPv6 www.auth0.com has 2 IPv6 addresses and answers on every one we tested. ✓ 2a06:98c1:310b::6812:2512 answers · 443✓ 2606:4700:4407::ac40:96ee answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. mxa-00553301.gslb.pphosted.com ✗mxb-00553301.gslb.pphosted.com ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. kolton.ns.cloudflare.com ✓monroe.ns.cloudflare.com ✓	yes

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 200.

https://auth0.com/ via 2a06:98c1:310b::6812:2512 → 200

works

What's keeping auth0.com from an A

Mail servers without IPv6
mxa-00553301.gslb.pphosted.com, mxb-00553301.gslb.pphosted.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

auth0.com Has IPv6

A (IPv4)	104.18.37.18 172.64.150.238
AAAA (IPv6)	2a06:98c1:310b::6812:2512 2606:4700:4407::ac40:96ee

www.auth0.com Has IPv6

A (IPv4)	104.18.37.18 172.64.150.238
AAAA (IPv6)	2a06:98c1:310b::6812:2512 2606:4700:4407::ac40:96ee

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: auth0.com
Measured 2026-10-31 05:04:33 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.18.37.18, 172.64.150.238
AAAA (IPv6): 2a06:98c1:310b::6812:2512, 2606:4700:4407::ac40:96ee
www AAAA:    2a06:98c1:310b::6812:2512, 2606:4700:4407::ac40:96ee

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: auth0.com has 2 IPv6 addresses and answers on every one we tested.
    2a06:98c1:310b::6812:2512: answers (TCP 443)
    2606:4700:4407::ac40:96ee: answers (TCP 443)
- www over IPv6: www.auth0.com has 2 IPv6 addresses and answers on every one we tested.
    2a06:98c1:310b::6812:2512: answers (TCP 443)
    2606:4700:4407::ac40:96ee: answers (TCP 443)
- Mail servers (MX) have IPv6: None of the mail servers has an AAAA record.
- Nameservers have IPv6: 2 of 2 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): Loads over IPv6 with a valid certificate: HTTP 200.
    https://auth0.com/ via 2a06:98c1:310b::6812:2512 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/rwLtDgHUyw

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

Checked 2026-10-31 05:04:33 UTC — one of the top 1,000 sites, re-checked weekly. Re-check now. Full DNS report: dns.pizza/domain/auth0.com · JSON: /api/v1/auth0.com