Yes — mdpi.com has IPv6.

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

B
IPv6 readiness
Works over IPv6, with one gap: its mail servers lack IPv6.
Website over IPv6
mdpi.com has 4 IPv6 addresses and answers on every one we tested (1 more not tested).
✓ 2600:1408:5400:35::17ca:e6e2 answers · 443✓ 2600:1408:5400:35::17ca:e6e0 answers · 443✓ 2600:1408:5400:35::17ca:e6c8 answers · 443✓ 2600:1408:5400:35::17ca:e6de answers · 443– 2600:1408:5400:35::17ca:e6df not tested
yes
www over IPv6
www.mdpi.com has 4 IPv6 addresses and answers on every one we tested (1 more not tested).
✓ 2600:1408:5400:35::17ca:e6ca answers · 443✓ 2600:1408:5400:35::17ca:e6dd answers · 443✓ 2600:1408:5400:35::17ca:e6da answers · 443✓ 2600:1408:5400:35::17ca:e6cb answers · 443– 2600:1408:5400:35::17ca:e6d0 not tested
yes
Mail servers (MX) have IPv6
None of the mail servers has an AAAA record.
mail.mdpi.com ✗
no
Nameservers have IPv6
2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.
duke.ns.cloudflare.com ✓tia.ns.cloudflare.com ✓
yes
HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate: HTTP 403.
https://mdpi.com/ via 2600:1408:5400:35::17ca:e6df → 403
works
 Load mdpi.com over IPv6 from up to six other places — a second opinion.

What's keeping mdpi.com from an A

  1. Mail servers without IPv6
    mail.mdpi.com 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

mdpi.com  Has IPv6

A (IPv4)23.202.230.199
23.202.230.203
AAAA (IPv6)2600:1408:5400:35::17ca:e6e2
2600:1408:5400:35::17ca:e6e0
2600:1408:5400:35::17ca:e6c8
2600:1408:5400:35::17ca:e6de
2600:1408:5400:35::17ca:e6df

www.mdpi.com  Has IPv6

Alias ofwww.mdpi.com.edgekey.net → e316778.dscb.akamaiedge.net
A (IPv4)23.48.203.43
23.48.203.37
AAAA (IPv6)2600:1408:5400:35::17ca:e6ca
2600:1408:5400:35::17ca:e6dd
2600:1408:5400:35::17ca:e6da
2600:1408:5400:35::17ca:e6cb
2600:1408:5400:35::17ca:e6d0

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/4kL1zcf_mP · How we measure

Checked 2026-10-31 20:12:46 UTC. Full DNS report: dns.pizza/domain/mdpi.com · JSON: /api/v1/mdpi.com