Yes — signbox.online has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 signbox.online has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3030::ac43:8b63 answers · 443✓ 2606:4700:3037::6815:4114 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. route3.mx.cloudflare.net ✓route1.mx.cloudflare.net ✓route2.mx.cloudflare.net ✓	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. brett.ns.cloudflare.com ✓serenity.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://signbox.online/ via 2606:4700:3030::ac43:8b63 → 307https://signbox.online/login via 2606:4700:3030::ac43:8b63 → 200

works

Nothing keeping you from an A

Nothing to fix
Show it off: add the badge to your README.
[![IPv6](https://aaaa.bot/badge/signbox.online.svg)](https://aaaa.bot/signbox.online)

Check again

signbox.online Has IPv6

A (IPv4)	104.21.65.20 172.67.139.99
AAAA (IPv6)	2606:4700:3030::ac43:8b63 2606:4700:3037::6815:4114

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: signbox.online
Measured 2026-11-05 20:28:08 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.21.65.20, 172.67.139.99
AAAA (IPv6): 2606:4700:3030::ac43:8b63, 2606:4700:3037::6815:4114

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: signbox.online has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3030::ac43:8b63: answers (TCP 443)
    2606:4700:3037::6815:4114: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server 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 after 1 redirect: HTTP 200.
    https://signbox.online/ via 2606:4700:3030::ac43:8b63 -> HTTP 307, certificate: valid
    https://signbox.online/login via 2606:4700:3030::ac43:8b63 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/V5OSS_PasY

Permanent link: aaaa.bot/r/V5OSS_PasY · How we measure

Checked 2026-11-05 20:28:08 UTC. Full DNS report: dns.pizza/domain/signbox.online · Age, certificate and blocklists: how.is/signbox.online · JSON: /api/v1/signbox.online