Yes — ycombinator.com has IPv6.

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

This is a saved measurement from 2026-11-02 03:30 UTC. Check ycombinator.com live now

B
IPv6 readiness
Works over IPv6, with one gap: www doesn't fully work over IPv6.
Website over IPv6
ycombinator.com has 4 IPv6 addresses and answers on every one we tested (4 more not tested).
✓ 2600:9000:2508:d400:15:891f:4040:93a1 answers · 443✓ 2600:9000:2508:1c00:15:891f:4040:93a1 answers · 443✓ 2600:9000:2508:c200:15:891f:4040:93a1 answers · 443✓ 2600:9000:2508:da00:15:891f:4040:93a1 answers · 443– 2600:9000:2508:b800:15:891f:4040:93a1 not tested– 2600:9000:2508:7200:15:891f:4040:93a1 not tested– 2600:9000:2508:4800:15:891f:4040:93a1 not tested– 2600:9000:2508:2c00:15:891f:4040:93a1 not tested
yes
www over IPv6
www.ycombinator.com has no AAAA record.		no
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 ✓aspmx4.googlemail.com ✓
yes
Nameservers have IPv6
4 of 4 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
ns-1411.awsdns-48.org ✓ns-1914.awsdns-47.co.uk ✓ns-225.awsdns-28.com ✓ns-556.awsdns-05.net ✓
yes
HTTPS over IPv6 · not part of the grade yet
Redirects to www.ycombinator.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all.
https://ycombinator.com/ via 2600:9000:2508:d400:15:891f:4040:93a1 → 301https://www.ycombinator.com/ · redirects to www.ycombinator.com, which has no IPv6 address
problem

What's keeping ycombinator.com from an A

  1. www.ycombinator.com is an alias of www.ycombinator.com.cdn.cloudflare.net, which has no IPv6
    www.ycombinator.com is a CNAME, so it can't also have its own AAAA record. Ask whoever runs www.ycombinator.com.cdn.cloudflare.net to enable IPv6 there — or replace the alias with the A and AAAA records they give you. Why some hosts don't offer IPv6
  2. A redirect leads off IPv6
    Redirects to www.ycombinator.com, which has no IPv6 address — so IPv6 visitors end up needing IPv4 after all. Give the redirect target IPv6 too, or redirect somewhere that has it.

Check again

ycombinator.com  Has IPv6

A (IPv4)108.138.64.111
108.138.64.8
108.138.64.90
108.138.64.45
AAAA (IPv6)2600:9000:2508:d400:15:891f:4040:93a1
2600:9000:2508:1c00:15:891f:4040:93a1
2600:9000:2508:c200:15:891f:4040:93a1
2600:9000:2508:da00:15:891f:4040:93a1
2600:9000:2508:b800:15:891f:4040:93a1
2600:9000:2508:7200:15:891f:4040:93a1
2600:9000:2508:4800:15:891f:4040:93a1
2600:9000:2508:2c00:15:891f:4040:93a1

www.ycombinator.com  IPv4 only

Alias ofwww.ycombinator.com.cdn.cloudflare.net
A (IPv4)104.20.46.159
172.66.144.64
AAAA (IPv6)none

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

 Permanent link: aaaa.bot/r/HguaO-SL57 · How we measure

Checked 2026-11-02 03:30:19 UTC. Full DNS report: dns.pizza/domain/ycombinator.com · JSON: /api/v1/ycombinator.com