No — jhu.edu is IPv4 only.

Has an IPv4 address but no IPv6 (AAAA) record. IPv6-only visitors can't reach it directly.

Measured 2026-11-01 06:37 UTC. We reuse a result for up to a week, so we aren't testing the same site over and over. Check jhu.edu now

IPv6 readiness

The website has no IPv6.

Website over IPv6 jhu.edu has no AAAA record.	no
www over IPv6 www.jhu.edu has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:4400::ac40:9bb7 answers · 443✓ 2606:4700:440d::6812:2049 answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. smtp.johnshopkins.edu ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ens1.jhu.edu ✓ens1.jhmi.edu ✓	yes

First measured 2026-11-01; last confirmed 2026-11-01.

What's keeping jhu.edu from an A

Give jhu.edu an IPv6 address
Ask your hosting provider for the site's IPv6 address (or the hostname to point at), then publish it as an AAAA record. If your host doesn't offer IPv6, a proxy that does can sit in front. How to add an AAAA record
Mail servers without IPv6
smtp.johnshopkins.edu has no AAAA record, so mail from IPv6-only servers can't reach it directly. If a provider runs your mail, that's their setting; if you run it, add AAAA records for these hosts.

Check again

jhu.edu IPv4 only

A (IPv4)	128.220.193.2
AAAA (IPv6)	none

www.jhu.edu Has IPv6

Alias of	www.jhu.edu.cdn.cloudflare.net
A (IPv4)	172.64.155.183 104.18.32.73
AAAA (IPv6)	2606:4700:4400::ac40:9bb7 2606:4700:440d::6812:2049

What this means

Visitors on IPv6-only networks (many mobile carriers) can still reach it, but only through a translator their carrier runs (NAT64). The site itself has no IPv6 address — and you can't make one up from the IPv4. Why some hosts don't offer it

Copy the evidence — a citation-ready record of this measurement

IPv6 measurement: jhu.edu
Measured 2026-11-01 06:37:26 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    128.220.193.2
AAAA (IPv6): none
www AAAA:    2606:4700:4400::ac40:9bb7, 2606:4700:440d::6812:2049

Readiness grade D: The website has no IPv6.
- Website over IPv6: jhu.edu has no AAAA record.
- www over IPv6: www.jhu.edu has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:4400::ac40:9bb7: answers (TCP 443)
    2606:4700:440d::6812:2049: answers (TCP 443)
- Mail servers (MX) have IPv6: None of the mail servers has an AAAA record.
- Nameservers have IPv6: 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.

Reachability = a TCP connection opened on port 443 (or 80).
No TLS or HTTP request was made.
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/NJu9a7Vkrh

Permanent link: aaaa.bot/r/NJu9a7Vkrh · How we measure

Checked 2026-11-01 06:37:26 UTC. Full DNS report: dns.pizza/domain/jhu.edu · JSON: /api/v1/jhu.edu