kb.rocket.chat publishes IPv6 but doesn't answer on it.

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

F
IPv6 readiness
Publishes IPv6 but doesn't answer on it — worse than having none.
Website over IPv6
kb.rocket.chat has an AAAA record, but nothing answered on ports 443 or 80. IPv6 visitors wait for a timeout before falling back to IPv4.
✗ 2604:2dc0:100:1b42:: no answer✗ 2604:2dc0:100:2378:: no answer✗ 2604:2dc0:100:1b89:: no answer
broken
www over IPv6
www.kb.rocket.chat has an AAAA record, but nothing answered on ports 443 or 80. IPv6 visitors wait for a timeout before falling back to IPv4.
✗ 2604:2dc0:100:1b89:: no answer✗ 2604:2dc0:100:1b42:: no answer✗ 2604:2dc0:100:2378:: no answer
broken
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
4 of 4 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
ns-1367.awsdns-42.org ✓ns-1644.awsdns-13.co.uk ✓ns-510.awsdns-63.com ✓ns-652.awsdns-17.net ✓
yes
 Which outside scripts, fonts, payments or chat kb.rocket.chat loads from have no IPv6.
 Load kb.rocket.chat over IPv6 from up to six other places — a second opinion.

What's keeping kb.rocket.chat from an A

  1. Fix or remove the AAAA record for kb.rocket.chat
    Something published an IPv6 address but nothing answers on it, so IPv6 visitors wait for a timeout first. Either make the server listen on IPv6 (and allow ports 443/80 through its firewall), or delete the AAAA record until it does.
  2. Fix or remove the AAAA record for www.kb.rocket.chat
    Something published an IPv6 address but nothing answers on it, so IPv6 visitors wait for a timeout first. Either make the server listen on IPv6 (and allow ports 443/80 through its firewall), or delete the AAAA record until it does.

Check again

kb.rocket.chat  Has IPv6

A (IPv4)51.81.11.137
51.81.47.120
51.81.11.66
AAAA (IPv6)2604:2dc0:100:1b42::
2604:2dc0:100:2378::
2604:2dc0:100:1b89::

www.kb.rocket.chat  Has IPv6

A (IPv4)51.81.11.137
51.81.11.66
51.81.47.120
AAAA (IPv6)2604:2dc0:100:1b89::
2604:2dc0:100:1b42::
2604:2dc0:100:2378::

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/DOfM-N29XW · How we measure

Checked 2026-11-15 15:54:04 UTC. Full DNS report: dns.pizza/domain/kb.rocket.chat · Age, certificate and blocklists: how.is/kb.rocket.chat · JSON: /api/v1/kb.rocket.chat