marum.de

Checked 21 October 2026, 23:21 UTC · via 8.8.8.8
!Passed with warnings
27 passed 1 warning 0 failed 5 info

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

deneb.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
deneb.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.de
NS in the zone
deneb.dfn.de, ines.zfn.uni-bremen.de, ns.informatik.uni-bremen.de
NameserverAddressesNetwork (AS)Glue
deneb.dfn.de192.76.176.9 2001:638:800:1::9AS680 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.de134.102.20.20 2001:638:708:20::20AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.102.20.20 2001:638:708:20::20
ns.informatik.uni-bremen.de134.102.200.14 2001:638:708:30c8::14AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.102.200.14 2001:638:708:30c8::14

Checks

  • ✓ 3 nameservers #6
    Delegated to deneb.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.
  • ✓ No glue needed #8
    All nameservers are outside the zone, so no glue records are needed.
  • ✓ 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.
  • 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

NameserverAnswerRecursionTCP / EDNSAXFRVersion
deneb.dfn.de 192.76.176.9NOERROR, 15 ms, authoritativenoyes / yesrefused0
deneb.dfn.de 2001:638:800:1::9NOERROR, 15 ms, authoritativenoyes / yesrefused0
ines.zfn.uni-bremen.de 134.102.20.20NOERROR, 12 ms, authoritativenoyes / yesrefusedNot supported
ines.zfn.uni-bremen.de 2001:638:708:20::20NOERROR, 12 ms, authoritativenoyes / yesrefusedNot supported
ns.informatik.uni-bremen.de 134.102.200.14NOERROR, 12 ms, authoritativenoyes / yesrefused9.20.29
ns.informatik.uni-bremen.de 2001:638:708:30c8::14NOERROR, 12 ms, authoritativenoyes / yesrefused9.20.29

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 2026102041 · primary ines.zfn.uni-bremen.de

Found

Primary (MNAME)
ines.zfn.uni-bremen.de
Contact (RNAME)
helms.zfn.uni-bremen.de
Serial
2026102041
Refresh / retry
28800 s / 7200 s
Expire
1209600 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
deneb.dfn.de (192.76.176.9)2026102041
deneb.dfn.de (2001:638:800:1::9)2026102041
ines.zfn.uni-bremen.de (134.102.20.20)2026102041
ines.zfn.uni-bremen.de (2001:638:708:20::20)2026102041
ns.informatik.uni-bremen.de (134.102.200.14)2026102041
ns.informatik.uni-bremen.de (2001:638:708:30c8::14)2026102041

Checks

  • ✓ Serial 2026102041 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 8h, retry 2h, expire 14d, negative TTL 1d.
  • ✓ 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.
  • ✓ Date-based serial #26
    The serial 2026102041 follows the YYYYMMDDnn convention (2026-10-20).

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 tagAlgorithmDigestMatches a key
19576RSASHA256 (8)SHA256 FFF19CF2D4658088…yes

DNSKEY in the zone

Key tagRoleAlgorithm
19576KSK (257)RSASHA256 (8)
60348ZSK (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 19576 (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.
  • i
    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

15 records at the apex

Found

Read from
192.76.176.9:53
TypeValueTTL
SOAines.zfn.uni-bremen.de. helms.zfn.uni-bremen.de. 2026102041 28800 7200 1209600 8640086400
NSdeneb.dfn.de.86400
NSns.informatik.uni-bremen.de.86400
NSines.zfn.uni-bremen.de.86400
A134.102.234.6386400
MX10 mail1.marum.de.86400
MX20 mail2.marum.de.86400
TXT"MS=ms37500307"86400
TXT"apple-domain-verification=0IWMyzgkEH2sILix"86400
TXT"google-site-verification=tLzQWruBqInkZ0FPO8Lve0Nl0dTok0IBNbzYLBVwhz0"86400
TXT"v=spf1 mx ip4:134.102.234.15 ip4:134.102.234.17 ip4:134.102.234.18 ip4:134.102.234.19 ip4:134.102.234.37 ip4:134.102.234.126 ip4:134.102.234.56 include:spf.eprov.eu a:marumfreunde.de -all"86400
CAA0 issue "letsencrypt.org"86400
CAA0 issuewild "harica.gr"86400
CAA0 issue "harica.gr"86400
CAA0 issue "pki.dfn.de"86400

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.
  • ✓ CAA restricts issuance #35
    Certificates may be issued by: letsencrypt.org, harica.gr, pki.dfn.de.