Domain report: uni-bremen.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

dns-2.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.de

Found

Parent zone: de
Delegation from: a.nic.de (194.0.0.53)
NS at the parent: dns-2.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.de
NS in the zone: dns-2.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.de

Nameserver	Addresses	Network (AS)	Glue
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	-
ines.zfn.uni-bremen.de	134.102.20.20 2001:638:708:20::20	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	134.102.20.20 2001:638:708:20::20
ns.informatik.uni-bremen.de	134.102.200.14 2001:638:708:30c8::14	AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE	134.102.200.14 2001:638:708:30c8::14

Checks

✓ 3 nameservers #6

Delegated to dns-2.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.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: ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.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 3 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): 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
dns-2.dfn.de 193.174.75.54	NOERROR, 6 ms, authoritative	no	yes / yes	refused	0
dns-2.dfn.de 2001:638:d:b102::1	NOERROR, 6 ms, authoritative	no	yes / yes	refused	0
ines.zfn.uni-bremen.de 134.102.20.20	NOERROR, 12 ms, authoritative	no	yes / yes	refused	Not supported
ines.zfn.uni-bremen.de 2001:638:708:20::20	NOERROR, 15 ms, authoritative	no	yes / yes	refused	Not supported
ns.informatik.uni-bremen.de 134.102.200.14	NOERROR, 12 ms, authoritative	no	yes / yes	refused	9.20.29
ns.informatik.uni-bremen.de 2001:638:708:30c8::14	NOERROR, 12 ms, authoritative	no	yes / yes	refused	9.20.29

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: ns.informatik.uni-bremen.de: "9.20.29". 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 2030887949 · primary ines.zfn.uni-bremen.de

Found

Primary (MNAME): ines.zfn.uni-bremen.de
Contact (RNAME): helms.zfn.uni-bremen.de
Serial: 2030887949
Refresh / retry: 28800 s / 7200 s
Expire: 1209600 s
Negative TTL: 1400 s

Serial per nameserver

Nameserver	Serial
dns-2.dfn.de (193.174.75.54)	2030887949
dns-2.dfn.de (2001:638:d:b102::1)	2030887949
ines.zfn.uni-bremen.de (134.102.20.20)	2030887949
ines.zfn.uni-bremen.de (2001:638:708:20::20)	2030887949
ns.informatik.uni-bremen.de (134.102.200.14)	2030887949
ns.informatik.uni-bremen.de (2001:638:708:30c8::14)	2030887949

Checks

✓ Serial 2030887949 everywhere #22

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

SOA refresh 8h, retry 2h, expire 14d, negative TTL 23m20s.
✓ Primary is a public nameserver #24

The primary nameserver ines.zfn.uni-bremen.de is one of the listed nameservers.
✓ Contact helms@zfn.uni-bremen.de #25

The SOA RNAME helms.zfn.uni-bremen.de means helms@zfn.uni-bremen.de.
✓ Timestamp serial #26

The serial 2030887949 is a Unix timestamp (2034-05-10 15:32 UTC).

DNSSEC

info

Signed, DS published at parent

Found

Validated by resolver: yes
Denial of existence: NSEC
Signatures valid until: 20 November 2026

DS at the parent

Key tag	Algorithm	Digest	Matches a key
18877	RSASHA256 (8)	SHA256 CA9990131EF2ECB4…	yes

DNSKEY in the zone

Key tag	Role	Algorithm
15315	ZSK (256)	RSASHA256 (8)
18877	KSK (257)	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 18877 (SHA256).
✓ Modern algorithms #29

Key algorithms: RSASHA256 (8).
✓ Signatures valid until 2026-11-20 #30

The earliest DNSKEY/SOA signature expires at 2026-11-20 16:10 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

pass

21 records at the apex

Found

Read from: 193.174.75.54:53

Type	Value	TTL
SOA	ines.zfn.uni-bremen.de. helms.zfn.uni-bremen.de. 2030887949 28800 7200 1209600 1400	1400
NS	dns-2.dfn.de.	1400
NS	ns.informatik.uni-bremen.de.	1400
NS	ines.zfn.uni-bremen.de.	1400
A	134.102.22.124	1400
AAAA	2001:638:708:16::22:124	1400
MX	10 mailgate.zfn.uni-bremen.de.	1400
TXT	"google-site-verification=uADf_FvqD49vqW1R7ZpDJVjm1LuOkCt4oHGGfv8oAhE"	1400
TXT	"nitro-verification-code=Nzc1MTU4MjgxMTQ3NjE5MTc1Mw=="	1400
TXT	"v=spf1 a mx ip4:134.102.50.0/24 ip6:2001:638:708:32::/64 ip4:134.102.51.0/24 ip4:134.102.58.0/24 ip4:134.102.3.75 ip4:134.102.236.10 ip4:134.102.196.32 ip4:134.102.20.0/24 ip4:134.102.22.0/23 ip4:134.102.231.91 include:_spf.zimpel.de ~all"	1400
TXT	"ms=644922E0CDD80E313DAF6BAC6974F8BD19938702"	1400
TXT	"google-site-verification=b6v9hpU4xxZKeTqeb1JuIn8T1QS2Jjkrj07pVCB1aBk"	1400
TXT	"cisco-ci-domain-verification=3a8a59fb2fba7134712d7ac41a382a678e7d28ef02f69cce25ba58e5e5e332c4"	1400
TXT	"google-site-verification=BqjtWc7qOcV2hSUUwPTIja-PFBVVctvEsskJo4S8RrM"	1400
TXT	"HARICA-gaXa3ISBZAriIptMjvp"	1400
TXT	"_telesec-domain-validation=342062_2025-10-30_iBR3iEre5Q4rBZHu4P54hgxq6GUBD4r9VQrylGxHWR63Kbcrud"	1400
CAA	0 issuewild "harica.gr"	1400
CAA	0 issue "pki.dfn.de"	1400
CAA	0 iodef "mailto:campusserver@uni-bremen.de "	1400
CAA	0 issue "harica.gr"	1400
CAA	0 issue "telesec.de"	1400

Checks

✓ TTLs within range #32

TTLs: A 23m20s, AAAA 23m20s, MX 23m20s, NS 23m20s. The NS TTL at the parent is 1d and in the zone 23m20s; resolvers may use either.
✓ 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: harica.gr, pki.dfn.de, telesec.de.