Domain report: ku.de

Registration

info

.de country-code

Found

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

Checks

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.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

dns-1.dfn.de, dns-3.dfn.de, ns.ku.de, ns3.rrze.uni-erlangen.de

Found

Parent zone: de
Delegation from: a.nic.de (194.0.0.53)
NS at the parent: dns-1.dfn.de, dns-3.dfn.de, ns.ku.de, ns3.rrze.uni-erlangen.de
NS in the zone: dns-1.dfn.de, dns-3.dfn.de, ns.ku.de, ns3.rrze.uni-erlangen.de

Nameserver	Addresses	Network (AS)	Glue
dns-1.dfn.de	193.174.75.50 2001:638:d:b101::1	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	-
dns-3.dfn.de	193.174.75.58 2001:638:d:b103::1	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	-
ns.ku.de	141.78.7.250	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	141.78.7.250
ns3.rrze.uni-erlangen.de	131.188.0.52 131.188.3.4 2001:638:a000:1055:53::3 2001:638:a000:1001:53::3	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	-

Checks

✓ 4 nameservers #6

Delegated to dns-1.dfn.de, dns-3.dfn.de, ns.ku.de, ns3.rrze.uni-erlangen.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: ns.ku.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 4 IPv4 /24s and 2 IPv6 /48s.
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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): 9 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.

#11
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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
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Partly IPv6

These nameservers have no IPv6 address: ns.ku.de.

#13

Nameservers

warn

9 of 9 addresses answer authoritatively

Found

Nameserver	Answer	Recursion	TCP / EDNS	AXFR	Version
dns-1.dfn.de 193.174.75.50	NOERROR, 12 ms, authoritative	no	yes / yes	refused	0
dns-1.dfn.de 2001:638:d:b101::1	NOERROR, 12 ms, authoritative	no	yes / yes	refused	0
dns-3.dfn.de 193.174.75.58	NOERROR, 10 ms, authoritative	no	yes / yes	refused	0
dns-3.dfn.de 2001:638:d:b103::1	NOERROR, 10 ms, authoritative	no	yes / yes	refused	0
ns.ku.de 141.78.7.250	NOERROR, 8 ms, authoritative	no	yes / yes	refused	9.11.22
ns3.rrze.uni-erlangen.de 131.188.0.52	NOERROR, 7 ms, authoritative	no	yes / yes	refused	-
ns3.rrze.uni-erlangen.de 131.188.3.4	NOERROR, 7 ms, authoritative	no	yes / yes	refused	-
ns3.rrze.uni-erlangen.de 2001:638:a000:1055:53::3	NOERROR, 7 ms, authoritative	no	yes / yes	refused	-
ns3.rrze.uni-erlangen.de 2001:638:a000:1001:53::3	NOERROR, 7 ms, authoritative	no	yes / yes	refused	-

Checks

✓ All respond #14

All 9 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: ns.ku.de: "9.11.22". 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 202637107 · primary ns.ku.de

Found

Primary (MNAME): ns.ku.de
Contact (RNAME): netzadm.ku.de
Serial: 202637107
Refresh / retry: 21600 s / 3600 s
Expire: 3600000 s
Negative TTL: 86400 s

Serial per nameserver

Nameserver	Serial
dns-1.dfn.de (193.174.75.50)	202637107
dns-1.dfn.de (2001:638:d:b101::1)	202637107
dns-3.dfn.de (193.174.75.58)	202637107
dns-3.dfn.de (2001:638:d:b103::1)	202637107
ns.ku.de (141.78.7.250)	202637107
ns3.rrze.uni-erlangen.de (131.188.0.52)	202637107
ns3.rrze.uni-erlangen.de (131.188.3.4)	202637107
ns3.rrze.uni-erlangen.de (2001:638:a000:1055:53::3)	202637107
ns3.rrze.uni-erlangen.de (2001:638:a000:1001:53::3)	202637107

Checks

✓ Serial 202637107 everywhere #22

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

SOA refresh 6h, retry 1h, expire 1000h, negative TTL 1d.
✓ Primary is a public nameserver #24

The primary nameserver ns.ku.de is one of the listed nameservers.
✓ Contact netzadm@ku.de #25

The SOA RNAME netzadm.ku.de means netzadm@ku.de.
✓ Counter serial #26

The serial 202637107 is a plain counter.

DNSSEC

info

Signed, DS published at parent

Found

Validated by resolver: yes
Denial of existence: NSEC
Signatures valid until: 14 November 2026

DS at the parent

Key tag	Algorithm	Digest	Matches a key
47166	RSASHA512 (10)	SHA256 E90AEB0C5963A840…	yes

DNSKEY in the zone

Key tag	Role	Algorithm
4487	ZSK (256)	RSASHA512 (10)
47166	KSK (257)	RSASHA512 (10)

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 47166 (SHA256).
✓ Modern algorithms #29

Key algorithms: RSASHA512 (10).
✓ Signatures valid until 2026-11-14 #30

The earliest DNSKEY/SOA signature expires at 2026-11-14 20:34 UTC.
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NSEC

The zone uses NSEC, so its full contents can be listed by walking the NSEC chain. That is fine unless the names are sensitive.

#31

Records

info

16 records at the apex

Found

Read from: 193.174.75.50:53

Type	Value	TTL
SOA	ns.ku.de. netzadm.ku.de. 202637107 21600 3600 3600000 86400	86400
NS	dns-1.dfn.de.	86400
NS	ns.ku.de.	86400
NS	ns3.rrze.uni-erlangen.de.	86400
NS	dns-3.dfn.de.	86400
A	141.78.7.198	86400
MX	10 c1041.mx.srv.dfn.de.	86400
MX	10 b1041.mx.srv.dfn.de.	86400
MX	10 a1041.mx.srv.dfn.de.	86400
TXT	"adobe-idp-site-verification=d4cdce37079df62376fd999e8025c400e1940edaa74fe99ddeeab8d8b5d99729"	3600
TXT	"v=spf1 ip4:141.78.0.0/18 ip4:141.78.64.0/19 ip4:141.78.96.0/22 ip4:141.78.104.0/21 ip4:141.78.112.0/20 ip4:141.78.192.0/18 a:bvbvxmail.bib-bvb.de a:mailer02.zib.de ip4:5.9.79.165 ip4:159.69.247.208 ip4:23.88.47.24 include:mailgun.org ~all"	3600
TXT	"apple-domain-verification=497qMZv7r5v1n6iC"	3600
TXT	"google-site-verification=or3zmlmQAEZd_z3cUDTm23MXGZF0XdOvUdieC-hVzIU"	3600
TXT	"MS=FFD6B770542665E4F0A14DC1F7F5199DB1ED3075"	3600
TXT	"google-site-verification=eUCVOD4Wmcs9961Pt65s-V8hmv8RPY2D2j-0EGhVhPw"	3600
TXT	"facebook-domain-verification=86dqwz7qhtmht0hpynl65cfdh5mf29"	3600

Checks

✓ TTLs within range #32

TTLs: A 1d, MX 1d, 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.
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No CAA records

Without CAA records any certificate authority may issue certificates for this domain. A CAA record limits issuance to the CAs you use.

#35