Yes — slevomat.cz has IPv6.

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

Measured 2026-11-04 18:37 UTC. We reuse a result for up to a week, so we aren't testing the same site over and over. Check slevomat.cz now

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 slevomat.cz has 3 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:20::681a:d answers · 443✓ 2606:4700:20::681a:10d answers · 443✓ 2606:4700:20::ac43:481e answers · 443	yes
www over IPv6 www.slevomat.cz has 3 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:20::681a:d answers · 443✓ 2606:4700:20::681a:10d answers · 443✓ 2606:4700:20::ac43:481e answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. aspmx.l.google.com ✓alt1.aspmx.l.google.com ✓alt2.aspmx.l.google.com ✓alt3.aspmx.l.google.com ✓alt4.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. mimi.ns.cloudflare.com ✓felicity.ns.cloudflare.com ✓	yes

First measured 2026-11-04; last confirmed 2026-11-04.

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 403.

https://slevomat.cz/ via 2606:4700:20::681a:d → 403

works

Nothing keeping you from an A

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

Check again

slevomat.cz Has IPv6

A (IPv4)	104.26.0.13 104.26.1.13 172.67.72.30
AAAA (IPv6)	2606:4700:20::681a:d 2606:4700:20::681a:10d 2606:4700:20::ac43:481e

www.slevomat.cz Has IPv6

A (IPv4)	104.26.1.13 172.67.72.30 104.26.0.13
AAAA (IPv6)	2606:4700:20::681a:d 2606:4700:20::681a:10d 2606:4700:20::ac43:481e

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: slevomat.cz
Measured 2026-11-04 18:37:14 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.26.0.13, 104.26.1.13, 172.67.72.30
AAAA (IPv6): 2606:4700:20::681a:d, 2606:4700:20::681a:10d, 2606:4700:20::ac43:481e
www AAAA:    2606:4700:20::681a:d, 2606:4700:20::681a:10d, 2606:4700:20::ac43:481e

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: slevomat.cz has 3 IPv6 addresses and answers on every one we tested.
    2606:4700:20::681a:d: answers (TCP 443)
    2606:4700:20::681a:10d: answers (TCP 443)
    2606:4700:20::ac43:481e: answers (TCP 443)
- www over IPv6: www.slevomat.cz has 3 IPv6 addresses and answers on every one we tested.
    2606:4700:20::681a:d: answers (TCP 443)
    2606:4700:20::681a:10d: answers (TCP 443)
    2606:4700:20::ac43:481e: 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: HTTP 403.
    https://slevomat.cz/ via 2606:4700:20::681a:d -> HTTP 403, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/kOXJzupk2x

Permanent link: aaaa.bot/r/kOXJzupk2x · How we measure

Checked 2026-11-04 18:37:14 UTC. Full DNS report: dns.pizza/domain/slevomat.cz · Age, certificate and blocklists: how.is/slevomat.cz · JSON: /api/v1/slevomat.cz