Domain report: tuhh.de

Registration

info

.de country-code

Found

TLD: .de (country-code)
ICANN policies apply: no

Checks

i

.de is a country-code TLD (ccTLD)

Country-code TLD: governed by its local registry under national policy, not by an ICANN contract. Registrar accreditation, dispute resolution and RDAP/WHOIS rules are set by the registry.

#1
✓ TLD delegated and signed #2

.de is delegated in the root zone and DNSSEC-signed.
i

Registration data not available

No registration data via RDAP: the registry of .de offers no RDAP service. Many ccTLD registries don't offer RDAP; check the registry's WHOIS instead.

#3

Delegation

info

authdns1.rz.tuhh.de, authdns2.rz.tuhh.de, dns-2.dfn.de

Found

Parent zone: de
Delegation from: a.nic.de (194.0.0.53)
NS at the parent: authdns1.rz.tuhh.de, authdns2.rz.tuhh.de, dns-2.dfn.de
NS in the zone: authdns1.rz.tuhh.de, authdns2.rz.tuhh.de, dns-2.dfn.de

Nameserver	Addresses	Network (AS)	Glue
authdns1.rz.tuhh.de	134.28.205.116 2001:638:702:20bc::205:116	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	134.28.205.116 2001:638:702:20bc::205:116
authdns2.rz.tuhh.de	134.28.205.117 2001:638:702:20bc::205:117	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	134.28.205.117 2001:638:702:20bc::205:117
dns-2.dfn.de	193.174.75.54 2001:638:d:b102::1	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	-

Checks

✓ 3 nameservers #6

Delegated to authdns1.rz.tuhh.de, authdns2.rz.tuhh.de, dns-2.dfn.de.
✓ Parent and zone agree #7

The parent delegation and the zone's NS records list the same nameservers.
✓ Glue present and correct #8

Glue is published for the nameservers inside the zone: authdns1.rz.tuhh.de, authdns2.rz.tuhh.de.
✓ All names resolve #9

Every nameserver name has an address and is not an alias.
✓ Nameservers in different networks #10

The nameservers are spread over 2 IPv4 /24s and 2 IPv6 /48s.
i

All nameservers in one AS

All nameserver addresses are announced by one network operator (AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 6 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.

#11
i

All nameserver names under .de

All nameserver names are under one TLD, so a problem with that TLD also makes the nameservers unreachable. Some operators use names under two TLDs for extra resilience.

#12
✓ All reachable over IPv6 #13

Every nameserver has an IPv6 address.

Nameservers

warn

6 of 6 addresses answer authoritatively

Found

Nameserver	Answer	Recursion	TCP / EDNS	AXFR	Version
authdns1.rz.tuhh.de 134.28.205.116	NOERROR, 18 ms, authoritative	no	yes / yes	refused	9.18
authdns1.rz.tuhh.de 2001:638:702:20bc::205:116	NOERROR, 23 ms, authoritative	no	yes / yes	refused	9.18
authdns2.rz.tuhh.de 134.28.205.117	NOERROR, 12 ms, authoritative	no	yes / yes	refused	9.18
authdns2.rz.tuhh.de 2001:638:702:20bc::205:117	NOERROR, 23 ms, authoritative	no	yes / yes	refused	9.18
dns-2.dfn.de 193.174.75.54	NOERROR, 7 ms, authoritative	no	yes / yes	refused	0
dns-2.dfn.de 2001:638:d:b102::1	NOERROR, 7 ms, authoritative	no	yes / yes	refused	0

Checks

✓ All respond #14

All 6 nameserver addresses answered.
✓ All authoritative #15

Every responding nameserver answers authoritatively for the zone.
✓ No recursion #16

The nameservers do not answer recursive queries for other domains.
!

Software version disclosed

These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: authdns1.rz.tuhh.de: "9.18"; authdns2.rz.tuhh.de: "9.18". Hide or replace the version string.

#17
✓ Zone transfers refused #18

No nameserver allows a zone transfer to the public.
✓ TCP supported #19

All nameservers answer over TCP.
✓ EDNS supported #20

All nameservers support EDNS(0).
✓ Public addresses #21

All nameserver addresses are publicly routable.

SOA

pass

serial 2026102102 · primary authdns1.rz.tuhh.de

Found

Primary (MNAME): authdns1.rz.tuhh.de
Contact (RNAME): hostmaster.tuhh.de
Serial: 2026102102
Refresh / retry: 10000 s / 5000 s
Expire: 3600000 s
Negative TTL: 3600 s

Serial per nameserver

Nameserver	Serial
authdns1.rz.tuhh.de (134.28.205.116)	2026102102
authdns1.rz.tuhh.de (2001:638:702:20bc::205:116)	2026102102
authdns2.rz.tuhh.de (134.28.205.117)	2026102102
authdns2.rz.tuhh.de (2001:638:702:20bc::205:117)	2026102102
dns-2.dfn.de (193.174.75.54)	2026102102
dns-2.dfn.de (2001:638:d:b102::1)	2026102102

Checks

✓ Serial 2026102102 everywhere #22

All nameservers serve the same version of the zone.
✓ Timers within recommendations #23

SOA refresh 2h46m40s, retry 1h23m20s, expire 1000h, negative TTL 1h.
✓ Primary is a public nameserver #24

The primary nameserver authdns1.rz.tuhh.de is one of the listed nameservers.
✓ Contact hostmaster@tuhh.de #25

The SOA RNAME hostmaster.tuhh.de means hostmaster@tuhh.de.
✓ Date-based serial #26

The serial 2026102102 follows the YYYYMMDDnn convention (2026-10-21).

DNSSEC

pass

Signed, DS published at parent

Found

Validated by resolver: yes
Denial of existence: NSEC3
NSEC3: 0 iterations, 0-byte salt
Signatures valid until: 16 November 2026

DS at the parent

Key tag	Algorithm	Digest	Matches a key
29677	RSASHA256 (8)	SHA256 63A12975E18B38AF…	yes

DNSKEY in the zone

Key tag	Role	Algorithm
29677	KSK (257)	RSASHA256 (8)
30816	ZSK (256)	RSASHA256 (8)

Checks

✓ Signed and validated #27

The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
✓ DS matches a key #28

The DS record at the parent matches a key in the zone: key tag 29677 (SHA256).
✓ Modern algorithms #29

Key algorithms: RSASHA256 (8).
✓ Signatures valid until 2026-11-16 #30

The earliest DNSKEY/SOA signature expires at 2026-11-16 11:26 UTC.
✓ NSEC3 as recommended #31

The zone uses NSEC3 with 0 iterations and no salt (RFC 9276).

Records

pass

14 records at the apex

Found

Read from: 134.28.205.116:53

Type	Value	TTL
SOA	authdns1.rz.tuhh.de. hostmaster.tuhh.de. 2026102102 10000 5000 3600000 3600	3600
NS	dns-2.dfn.de.	86400
NS	authdns1.rz.tuhh.de.	86400
NS	authdns2.rz.tuhh.de.	86400
A	134.28.209.8	3600
MX	25 smtp3.rz.tu-harburg.de.	3600
MX	5 smtp4.rz.tu-harburg.de.	3600
MX	15 smtp5.rz.tu-harburg.de.	3600
TXT	"v=spf1 redirect=_spf.tuhh.de"	3600
CAA	0 issue "pki.dfn.de"	3600
CAA	0 iodef "mailto:dfn-pki@tuhh.de"	3600
CAA	0 issue "letsencrypt.org"	3600
CAA	0 issue "harica.gr"	3600
CAA	0 issue "sectigo.com"	3600

Checks

✓ TTLs within range #32

TTLs: A 1h, MX 1h, NS 1d.
✓ No CNAME at the apex #33

The zone apex has no CNAME record.
✓ No wildcard #34

Names that don't exist return NXDOMAIN.
✓ CAA restricts issuance #35

Certificates may be issued by: pki.dfn.de, letsencrypt.org, harica.gr, sectigo.com.