Yes — calendar.tcu.edu has IPv6.

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

IPv6 readiness

Works over IPv6, with gaps: www doesn't fully work over IPv6; its nameservers lack IPv6.

Website over IPv6 calendar.tcu.edu has an AAAA record and answers on it. ✓ 2603:1061:14:75::1 answers · 443	yes
www over IPv6 www.calendar.tcu.edu 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 No nameserver has an AAAA record — an IPv6-only resolver can't reach this domain's DNS. ns99.tcu.edu ✗ns1.tcu.edu ✗	no

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

https://calendar.tcu.edu/ via 2603:1061:14:75::1 → 200

works

What's keeping calendar.tcu.edu from an A

www.calendar.tcu.edu is an alias of webcommon10.it.tcu.edu, which has no IPv6
www.calendar.tcu.edu is a CNAME, so it can't also have its own AAAA record. Ask whoever runs webcommon10.it.tcu.edu to enable IPv6 there — or replace the alias with the A and AAAA records they give you. Why some hosts don't offer IPv6
Nameservers without IPv6
ns99.tcu.edu, ns1.tcu.edu all have no AAAA record, so a resolver that only speaks IPv6 can't look your domain up. Most DNS providers offer IPv6 nameservers; ask yours, or move DNS to one that does.

Check again

calendar.tcu.edu Has IPv6

Alias of	tcu.enterprise.localist.com → enterprise-web.localist.com → localist-production-ftgjadhqgwdqhbfp.z03.azurefd.net → mr-z03.tm-azurefd.net
A (IPv4)	150.171.109.113
AAAA (IPv6)	2603:1061:14:75::1

www.calendar.tcu.edu IPv4 only

Alias of	webcommon10.it.tcu.edu
A (IPv4)	138.237.38.30
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

IPv6 measurement: calendar.tcu.edu
Measured 2026-11-03 09:49:56 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    150.171.109.113
AAAA (IPv6): 2603:1061:14:75::1
www AAAA:    none

Readiness grade C: Works over IPv6, with gaps: www doesn't fully work over IPv6; its nameservers lack IPv6.
- Website over IPv6: calendar.tcu.edu has an AAAA record and answers on it.
    2603:1061:14:75::1: answers (TCP 443)
- www over IPv6: www.calendar.tcu.edu has no AAAA record.
- Mail servers (MX) have IPv6: No MX records, so mail goes to the domain's own address (implicit MX). It has an AAAA record.
- Nameservers have IPv6: No nameserver has an AAAA record — an IPv6-only resolver can't reach this domain's DNS.

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://calendar.tcu.edu/ via 2603:1061:14:75::1 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/x-9hTVSAJb

Permanent link: aaaa.bot/r/x-9hTVSAJb · How we measure

Checked 2026-11-03 09:49:56 UTC. Full DNS report: dns.pizza/domain/calendar.tcu.edu · Age, certificate and blocklists: how.is/calendar.tcu.edu · JSON: /api/v1/calendar.tcu.edu