Yes — calendar.colorado.edu has IPv6.

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

A
IPv6 readiness
Website, mail and DNS all work over IPv6.
Website over IPv6
calendar.colorado.edu has an AAAA record and answers on it.
✓ 2603:1061:14:47::1 answers · 443
yes
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
6 of 6 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
a2-67.akam.net ✓a20-65.akam.net ✓a1-153.akam.net ✓a3-66.akam.net ✓a22-67.akam.net ✓a11-66.akam.net ✓
yes
HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 200.
https://calendar.colorado.edu/ via 2603:1061:14:47::1 → 200
works
 Load calendar.colorado.edu over IPv6 from up to six other places — a second opinion.

Nothing keeping you from an A

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

Check again

calendar.colorado.edu  Has IPv6

Alias ofucboulder.enterprise.localist.com → enterprise-web.localist.com → localist-production-ftgjadhqgwdqhbfp.z03.azurefd.net → mr-z03.tm-azurefd.net
A (IPv4)150.171.109.118
AAAA (IPv6)2603:1061:14:47::1

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/7UumU3e3kH · How we measure

Checked 2026-11-03 07:03:13 UTC. Full DNS report: dns.pizza/domain/calendar.colorado.edu · Age, certificate and blocklists: how.is/calendar.colorado.edu · JSON: /api/v1/calendar.colorado.edu