Yes — master-demo.site 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 master-demo.site has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3035::6815:17e3 answers · 443✓ 2606:4700:3035::ac43:d5fc answers · 443	yes
www over IPv6 www.master-demo.site has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3035::ac43:d5fc answers · 443✓ 2606:4700:3035::6815:17e3 answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. eforward1.registrar-servers.com ✗eforward2.registrar-servers.com ✗eforward3.registrar-servers.com ✗eforward4.registrar-servers.com ✗eforward5.registrar-servers.com ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. clarissa.ns.cloudflare.com ✓patryk.ns.cloudflare.com ✓	yes

HTTPS over IPv6 · not part of the grade yet
More than 5 redirects — stopped following.

https://master-demo.site/ via 2606:4700:3035::6815:17e3 → 302https://master-demo.site/Account/Login?ReturnUrl=%2F via 2606:4700:3035::6815:17e3 → 302https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252F via 2606:4700:3035::6815:17e3 → 302https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252F via 2606:4700:3035::6815:17e3 → 302https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252FAccount%25252FLogin%25253FReturnUrl%25253D%2525252F via 2606:4700:3035::6815:17e3 → 302https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252FAccount%25252FLogin%25253FReturnUrl%25253D%2525252FAccount%2525252FLogin%2525253FReturnUrl%2525253D%252525252F via 2606:4700:3035::6815:17e3 → 302

What's keeping master-demo.site from an A

Mail servers without IPv6
eforward1.registrar-servers.com, eforward2.registrar-servers.com, eforward3.registrar-servers.com, eforward4.registrar-servers.com, eforward5.registrar-servers.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

master-demo.site Has IPv6

A (IPv4)	104.21.23.227 172.67.213.252
AAAA (IPv6)	2606:4700:3035::6815:17e3 2606:4700:3035::ac43:d5fc

www.master-demo.site Has IPv6

A (IPv4)	172.67.213.252 104.21.23.227
AAAA (IPv6)	2606:4700:3035::ac43:d5fc 2606:4700:3035::6815:17e3

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: master-demo.site
Measured 2026-11-04 03:15:39 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.21.23.227, 172.67.213.252
AAAA (IPv6): 2606:4700:3035::6815:17e3, 2606:4700:3035::ac43:d5fc
www AAAA:    2606:4700:3035::ac43:d5fc, 2606:4700:3035::6815:17e3

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: master-demo.site has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3035::6815:17e3: answers (TCP 443)
    2606:4700:3035::ac43:d5fc: answers (TCP 443)
- www over IPv6: www.master-demo.site has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3035::ac43:d5fc: answers (TCP 443)
    2606:4700:3035::6815:17e3: 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): More than 5 redirects — stopped following.
    https://master-demo.site/ via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
    https://master-demo.site/Account/Login?ReturnUrl=%2F via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
    https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252F via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
    https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252F via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
    https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252FAccount%25252FLogin%25253FReturnUrl%25253D%2525252F via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
    https://master-demo.site/Account/Login?ReturnUrl=%2FAccount%2FLogin%3FReturnUrl%3D%252FAccount%252FLogin%253FReturnUrl%253D%25252FAccount%25252FLogin%25253FReturnUrl%25253D%2525252FAccount%2525252FLogin%2525253FReturnUrl%2525253D%252525252F via 2606:4700:3035::6815:17e3 -> HTTP 302, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/O8vqmXJOze

Permanent link: aaaa.bot/r/O8vqmXJOze · How we measure

Checked 2026-11-04 03:15:39 UTC. Full DNS report: dns.pizza/domain/master-demo.site · Age, certificate and blocklists: how.is/master-demo.site · JSON: /api/v1/master-demo.site