Yes — a1sys.dev 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
a1sys.dev has 2 IPv6 addresses and answers on every one we tested.
✓ 2606:4700:3035::6815:4ee9 answers · 443✓ 2606:4700:3034::ac43:8a69 answers · 443
yes
www over IPv6
www.a1sys.dev has 2 IPv6 addresses and answers on every one we tested.
✓ 2606:4700:3035::6815:4ee9 answers · 443✓ 2606:4700:3034::ac43:8a69 answers · 443
yes
Mail servers (MX) have IPv6
None of the mail servers has an AAAA record.
mx.zoho.com ✗mx2.zoho.com ✗mx3.zoho.com ✗
no
Nameservers have IPv6
2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
amber.ns.cloudflare.com ✓nile.ns.cloudflare.com ✓
yes
HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.
https://a1sys.dev/ via 2606:4700:3035::6815:4ee9 → 301https://a1gbr.com/ via 2606:4700:3033::6815:5608 → 200
works
 Load a1sys.dev over IPv6 from up to six other places — a second opinion.

What's keeping a1sys.dev from an A

  1. Mail servers without IPv6
    mx.zoho.com, mx2.zoho.com, mx3.zoho.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

a1sys.dev  Has IPv6

A (IPv4)172.67.138.105
104.21.78.233
AAAA (IPv6)2606:4700:3035::6815:4ee9
2606:4700:3034::ac43:8a69

www.a1sys.dev  Has IPv6

A (IPv4)172.67.138.105
104.21.78.233
AAAA (IPv6)2606:4700:3035::6815:4ee9
2606:4700:3034::ac43:8a69

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/XeSKyE4wNr · How we measure

Checked 2026-10-31 04:53:07 UTC. Full DNS report: dns.pizza/domain/a1sys.dev · JSON: /api/v1/a1sys.dev