Yes — tacstack.org has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 tacstack.org has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3036::6815:4f13 answers · 443✓ 2606:4700:3030::ac43:a8b2 answers · 443	yes
www over IPv6 www.tacstack.org has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3036::6815:4f13 answers · 443✓ 2606:4700:3030::ac43:a8b2 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. aspmx.l.google.com ✓alt3.aspmx.l.google.com ✓alt4.aspmx.l.google.com ✓alt1.aspmx.l.google.com ✓alt2.aspmx.l.google.com ✓	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. dolly.ns.cloudflare.com ✓john.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://tacstack.org/ via 2606:4700:3036::6815:4f13 → 301https://tacstack.net/ via 2606:4700:20::681a:a8e → 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/tacstack.org.svg)](https://aaaa.bot/tacstack.org)

Check again

tacstack.org Has IPv6

A (IPv4)	172.67.168.178 104.21.79.19
AAAA (IPv6)	2606:4700:3036::6815:4f13 2606:4700:3030::ac43:a8b2

www.tacstack.org Has IPv6

A (IPv4)	172.67.168.178 104.21.79.19
AAAA (IPv6)	2606:4700:3036::6815:4f13 2606:4700:3030::ac43:a8b2

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: tacstack.org
Measured 2026-11-13 22:35:28 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    172.67.168.178, 104.21.79.19
AAAA (IPv6): 2606:4700:3036::6815:4f13, 2606:4700:3030::ac43:a8b2
www AAAA:    2606:4700:3036::6815:4f13, 2606:4700:3030::ac43:a8b2

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: tacstack.org has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3036::6815:4f13: answers (TCP 443)
    2606:4700:3030::ac43:a8b2: answers (TCP 443)
- www over IPv6: www.tacstack.org has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3036::6815:4f13: answers (TCP 443)
    2606:4700:3030::ac43:a8b2: 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://tacstack.org/ via 2606:4700:3036::6815:4f13 -> HTTP 301, certificate: valid
    https://tacstack.net/ via 2606:4700:20::681a:a8e -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/5FL34yMyam

Permanent link: aaaa.bot/r/5FL34yMyam · How we measure

Checked 2026-11-13 22:35:28 UTC. Full DNS report: dns.pizza/domain/tacstack.org · Age, certificate and blocklists: how.is/tacstack.org · JSON: /api/v1/tacstack.org