Yes — sleekint.xyz has IPv6.

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

IPv6 readiness

Works over IPv6, with one gap: its mail servers lack IPv6.

Website over IPv6 sleekint.xyz has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3036::6815:15fa answers · 443✓ 2606:4700:3030::ac43:c9a4 answers · 443	yes
www over IPv6 www.sleekint.xyz has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3036::6815:15fa answers · 443✓ 2606:4700:3030::ac43:c9a4 answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. mx2-hosting.jellyfish.systems ✗mx3-hosting.jellyfish.systems ✗mx1-hosting.jellyfish.systems ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. duke.ns.cloudflare.com ✓zainab.ns.cloudflare.com ✓	yes

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 200.

https://sleekint.xyz/ via 2606:4700:3036::6815:15fa → 200

works

What's keeping sleekint.xyz from an A

Mail servers without IPv6
mx2-hosting.jellyfish.systems, mx3-hosting.jellyfish.systems, mx1-hosting.jellyfish.systems 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

sleekint.xyz Has IPv6

A (IPv4)	104.21.21.250 172.67.201.164
AAAA (IPv6)	2606:4700:3036::6815:15fa 2606:4700:3030::ac43:c9a4

www.sleekint.xyz Has IPv6

A (IPv4)	172.67.201.164 104.21.21.250
AAAA (IPv6)	2606:4700:3036::6815:15fa 2606:4700:3030::ac43:c9a4

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: sleekint.xyz
Measured 2026-11-14 07:51:12 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.21.21.250, 172.67.201.164
AAAA (IPv6): 2606:4700:3036::6815:15fa, 2606:4700:3030::ac43:c9a4
www AAAA:    2606:4700:3036::6815:15fa, 2606:4700:3030::ac43:c9a4

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: sleekint.xyz has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3036::6815:15fa: answers (TCP 443)
    2606:4700:3030::ac43:c9a4: answers (TCP 443)
- www over IPv6: www.sleekint.xyz has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3036::6815:15fa: answers (TCP 443)
    2606:4700:3030::ac43:c9a4: answers (TCP 443)
- Mail servers (MX) have IPv6: None of the mail servers 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 200.
    https://sleekint.xyz/ via 2606:4700:3036::6815:15fa -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/y1mIwXU2Sv

Permanent link: aaaa.bot/r/y1mIwXU2Sv · How we measure

Checked 2026-11-14 07:51:12 UTC. Full DNS report: dns.pizza/domain/sleekint.xyz · Age, certificate and blocklists: how.is/sleekint.xyz · JSON: /api/v1/sleekint.xyz