Yes — gundersen.app has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 gundersen.app has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3032::ac43:a70a answers · 443✓ 2606:4700:3034::6815:39d7 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. route2.mx.cloudflare.net ✓route1.mx.cloudflare.net ✓route3.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. nadia.ns.cloudflare.com ✓stanley.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://gundersen.app/ via 2606:4700:3032::ac43:a70a → 302https://rapid-haze-dd1f.cloudflareaccess.com/cdn-cgi/access/login/gundersen.app?kid=25adc0b350e3a637c6f2368c375afa6f1e9774cd4eeb7673e5781ea85b3dc573&meta=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImtpZCI6Ijg2OGFmMjMzMzMwYTk2ZmFjNTUzMTBhMmQyN2E2MmQ1ZWM1YWY5Zjg3ZDBhOTg5OTNhMzk0MjZlMDg1NGI2NzcifQ.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.UwilJjxPOHu0X3xyQshO3Q9RcrQKWi2KTgXbk-rTm6zEkMstvl8ub7qA_agq9r3YkagTDBcM1Q1T9qatTFP1D3652kWnr4Pecl-yW6BvlQrSh4yculmddM2SbkFPOq3wVR9NuahJ_GLmie9lPa_-tddEwMzpeTj_gWzmlDS14D3vOq5JxL0S2hqjRFQn5OqkrGovTmT3BKI0LBgMknxYHJrLtHziuYwQgl1rMSuFgN6JUwcmDuOKwuXAhdVyEf6T6DB_TAsyzdn2fXBy3GkmXSPaLtWr3yGjLsH1wPKbKVHKi5kk6SEXnL1HpAM7g5HMYRpA4IbD7NvI4ODzgXlPVQ&redirect_url=%2F via 2606:4700:300a::6813:c21d → 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/gundersen.app.svg)](https://aaaa.bot/gundersen.app)

Check again

gundersen.app Has IPv6

A (IPv4)	172.67.167.10 104.21.57.215
AAAA (IPv6)	2606:4700:3032::ac43:a70a 2606:4700:3034::6815:39d7

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: gundersen.app
Measured 2026-11-14 04:42:30 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    172.67.167.10, 104.21.57.215
AAAA (IPv6): 2606:4700:3032::ac43:a70a, 2606:4700:3034::6815:39d7

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: gundersen.app has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3032::ac43:a70a: answers (TCP 443)
    2606:4700:3034::6815:39d7: 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://gundersen.app/ via 2606:4700:3032::ac43:a70a -> HTTP 302, certificate: valid
    https://rapid-haze-dd1f.cloudflareaccess.com/cdn-cgi/access/login/gundersen.app?kid=25adc0b350e3a637c6f2368c375afa6f1e9774cd4eeb7673e5781ea85b3dc573&meta=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImtpZCI6Ijg2OGFmMjMzMzMwYTk2ZmFjNTUzMTBhMmQyN2E2MmQ1ZWM1YWY5Zjg3ZDBhOTg5OTNhMzk0MjZlMDg1NGI2NzcifQ.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.UwilJjxPOHu0X3xyQshO3Q9RcrQKWi2KTgXbk-rTm6zEkMstvl8ub7qA_agq9r3YkagTDBcM1Q1T9qatTFP1D3652kWnr4Pecl-yW6BvlQrSh4yculmddM2SbkFPOq3wVR9NuahJ_GLmie9lPa_-tddEwMzpeTj_gWzmlDS14D3vOq5JxL0S2hqjRFQn5OqkrGovTmT3BKI0LBgMknxYHJrLtHziuYwQgl1rMSuFgN6JUwcmDuOKwuXAhdVyEf6T6DB_TAsyzdn2fXBy3GkmXSPaLtWr3yGjLsH1wPKbKVHKi5kk6SEXnL1HpAM7g5HMYRpA4IbD7NvI4ODzgXlPVQ&redirect_url=%2F via 2606:4700:300a::6813:c21d -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/8ccLw-0mO8

Permanent link: aaaa.bot/r/8ccLw-0mO8 · How we measure

Checked 2026-11-14 04:42:30 UTC. Full DNS report: dns.pizza/domain/gundersen.app · Age, certificate and blocklists: how.is/gundersen.app · JSON: /api/v1/gundersen.app