Yes — us.posthog.com has IPv6.

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

B
IPv6 readiness
Works over IPv6, with one gap: www doesn't fully work over IPv6.
Website over IPv6
us.posthog.com has 4 IPv6 addresses and answers on every one we tested (4 more not tested).
✓ 2600:1f18:4c12:9a02:b17b:b9ab:f713:5193 answers · 443✓ 2600:1f18:4c12:9a02:5fdd:d1a0:3186:805b answers · 443✓ 2600:1f18:4c12:9a01:11a3:54:b774:6d3c answers · 443✓ 2600:1f18:4c12:9a02:ff9b:2d63:329e:508b answers · 443– 2600:1f18:4c12:9a00:b356:e1f1:725f:bd6a not tested– 2600:1f18:4c12:9a00:92f7:cb1:25ef:7c61 not tested– 2600:1f18:4c12:9a01:351d:3bb2:e7b0:164 not tested– 2600:1f18:4c12:9a00:5d3f:6e8a:eb2e:aad not tested
yes
www over IPv6
www.us.posthog.com has no AAAA record.		no
Mail servers (MX) have IPv6
No MX records, so mail goes to the domain's own address (implicit MX). It has an AAAA record.		yes
Nameservers have IPv6
2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
rory.ns.cloudflare.com ✓julissa.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://us.posthog.com/ via 2600:1f18:4c12:9a02:b17b:b9ab:f713:5193 → 302https://us.posthog.com/login via 2600:1f18:4c12:9a02:b17b:b9ab:f713:5193 → 200
works
 Load us.posthog.com over IPv6 from up to six other places — a second opinion.

What's keeping us.posthog.com from an A

  1. Add IPv6 for www.us.posthog.com
    www.us.posthog.com has no AAAA record. Get www's IPv6 address from whoever hosts www and add it as an AAAA record. If the same server already serves both names (and its certificate covers www), you can reuse us.posthog.com's AAAA record(s) for www. How to add an AAAA record

Check again

us.posthog.com  Has IPv6

Alias ofposthog-ingress-prod-us-256455477.us-east-1.elb.amazonaws.com
A (IPv4)3.41.202.154
3.41.202.173
3.41.202.148
3.41.202.145
3.41.202.164
3.41.202.167
3.41.202.159
3.41.202.170
AAAA (IPv6)2600:1f18:4c12:9a02:b17b:b9ab:f713:5193
2600:1f18:4c12:9a02:5fdd:d1a0:3186:805b
2600:1f18:4c12:9a01:11a3:54:b774:6d3c
2600:1f18:4c12:9a02:ff9b:2d63:329e:508b
2600:1f18:4c12:9a00:b356:e1f1:725f:bd6a
2600:1f18:4c12:9a00:92f7:cb1:25ef:7c61
2600:1f18:4c12:9a01:351d:3bb2:e7b0:164
2600:1f18:4c12:9a00:5d3f:6e8a:eb2e:aad

www.us.posthog.com  No address

A (IPv4)none
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/UvHvmEM55l · How we measure

Checked 2026-11-01 20:28:28 UTC. Full DNS report: dns.pizza/domain/us.posthog.com · JSON: /api/v1/us.posthog.com