Yes — mail.univ-paris-diderot.fr has IPv6.

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

IPv6 readiness

Works over IPv6, with one gap: its mail servers lack IPv6.

Website over IPv6 mail.univ-paris-diderot.fr has an AAAA record and answers on it. ✓ 2001:660:3301:8008::230 answers · 443	yes
Mail servers (MX) have IPv6 At least one mail server has no AAAA record (2 of 3 checked do). shiva.jussieu.fr ✗korolev.univ-paris7.fr ✓potemkin.univ-paris7.fr ✓	partly
Nameservers have IPv6 2 of 3 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. shiva.jussieu.fr ✗korolev.univ-paris7.fr ✓potemkin.univ-paris7.fr ✓	yes

HTTPS over IPv6 · not part of the grade yet
The certificate served over IPv6 at 2001:660:3301:8008::230 isn't valid for mail.univ-paris-diderot.fr: UNABLE_TO_VERIFY_LEAF_SIGNATURE.

https://mail.univ-paris-diderot.fr/ via 2001:660:3301:8008::230 · UNABLE_TO_VERIFY_LEAF_SIGNATURE

problem

What's keeping mail.univ-paris-diderot.fr from an A

The certificate served over IPv6 is wrong
The certificate served over IPv6 at 2001:660:3301:8008::230 isn't valid for mail.univ-paris-diderot.fr: UNABLE_TO_VERIFY_LEAF_SIGNATURE. Often the IPv6 address points at a different server (or an old one) than IPv4 does. Make sure 2001:660:3301:8008::230 serves the same certificate as your IPv4 address.
Mail servers without IPv6
shiva.jussieu.fr 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

mail.univ-paris-diderot.fr Has IPv6

Alias of	rp3.dsi.univ-paris-diderot.fr
A (IPv4)	81.194.22.230
AAAA (IPv6)	2001:660:3301:8008::230

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: mail.univ-paris-diderot.fr
Measured 2026-10-31 21:04:24 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    81.194.22.230
AAAA (IPv6): 2001:660:3301:8008::230

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: mail.univ-paris-diderot.fr has an AAAA record and answers on it.
    2001:660:3301:8008::230: answers (TCP 443)
- Mail servers (MX) have IPv6: At least one mail server has no AAAA record (2 of 3 checked do).
- Nameservers have IPv6: 2 of 3 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).

HTTPS over IPv6 (not graded): The certificate served over IPv6 at 2001:660:3301:8008::230 isn't valid for mail.univ-paris-diderot.fr: UNABLE_TO_VERIFY_LEAF_SIGNATURE.
    https://mail.univ-paris-diderot.fr/ via 2001:660:3301:8008::230, certificate: UNABLE_TO_VERIFY_LEAF_SIGNATURE
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/Gm9jKHs-ra

Permanent link: aaaa.bot/r/Gm9jKHs-ra · How we measure

Checked 2026-10-31 21:04:24 UTC. Full DNS report: dns.pizza/domain/mail.univ-paris-diderot.fr · JSON: /api/v1/mail.univ-paris-diderot.fr