dfki.de

Checked 21 October 2026, 22:14 UTC · via 8.8.8.8
!Passed with warnings
22 passed 2 warnings 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, ns.informatik.uni-bremen.de, ns.rz.uni-saarland.de, ns1.dfki.de, ns2.dfki.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
deneb.dfn.de, ns.informatik.uni-bremen.de, ns.rz.uni-saarland.de, ns1.dfki.de, ns2.dfki.de
NS in the zone
deneb.dfn.de, ns.informatik.uni-bremen.de, ns.rz.uni-saarland.de, ns1.dfki.de, ns2.dfki.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-
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
ns.rz.uni-saarland.de134.96.7.7AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.96.7.7
ns1.dfki.de134.96.188.22AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.96.188.22
ns2.dfki.de134.96.188.27AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.96.188.27

Checks

  • ✓ 5 nameservers #6
    Delegated to deneb.dfn.de, ns.informatik.uni-bremen.de, ns.rz.uni-saarland.de, ns1.dfki.de, ns2.dfki.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: ns1.dfki.de, ns2.dfki.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.
  • 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): 7 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
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns.rz.uni-saarland.de, ns1.dfki.de, ns2.dfki.de.
    #13

Nameservers

warn

7 of 7 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
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
ns.rz.uni-saarland.de 134.96.7.7NOERROR, 8 ms, authoritativenoyes / yesrefused0
ns1.dfki.de 134.96.188.22NOERROR, 8 ms, authoritativenoyes / yesrefused9.18.30-0ubuntu0.20.04.2-Ubuntu
ns2.dfki.de 134.96.188.27NOERROR, 10 ms, authoritativenoyes / yesrefused9.18.30-0ubuntu0.20.04.2-Ubuntu

Checks

  • ✓ All respond #14
    All 7 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"; ns1.dfki.de: "9.18.30-0ubuntu0.20.04.2-Ubuntu"; ns2.dfki.de: "9.18.30-0ubuntu0.20.04.2-Ubuntu". 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 2026100700 · primary ns1.dfki.de

Found

Primary (MNAME)
ns1.dfki.de
Contact (RNAME)
hostmaster.dfki.de
Serial
2026100700
Refresh / retry
21600 s / 3600 s
Expire
3600000 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
deneb.dfn.de (192.76.176.9)2026100700
deneb.dfn.de (2001:638:800:1::9)2026100700
ns.informatik.uni-bremen.de (134.102.200.14)2026100700
ns.informatik.uni-bremen.de (2001:638:708:30c8::14)2026100700
ns.rz.uni-saarland.de (134.96.7.7)2026100700
ns1.dfki.de (134.96.188.22)2026100700
ns2.dfki.de (134.96.188.27)2026100700

Checks

  • ✓ Serial 2026100700 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 ns1.dfki.de is one of the listed nameservers.
  • ✓ Contact hostmaster@dfki.de #25
    The SOA RNAME hostmaster.dfki.de means hostmaster@dfki.de.
  • ✓ Date-based serial #26
    The serial 2026100700 follows the YYYYMMDDnn convention (2026-10-07).

DNSSEC

warn

Not signed

Found

Validated by resolver
no

Checks

  • !
    Not signed
    The zone is not signed with DNSSEC, so answers can be spoofed. Enable DNSSEC at your DNS provider and publish the DS record at your registrar.
    #27

Records

pass

18 records at the apex

Found

Read from
192.76.176.9:53
TypeValueTTL
SOAns1.dfki.de. hostmaster.dfki.de. 2026100700 21600 3600 3600000 8640086400
NSns1.dfki.de.86400
NSns2.dfki.de.86400
NSns.informatik.uni-bremen.de.86400
NSns.rz.uni-saarland.de.86400
NSdeneb.dfn.de.86400
A134.96.191.57600
MX0 dfki-de.mail.protection.outlook.com.3600
TXT"v=spf1 include:spf-sb.dfki.de include:spf-kl.dfki.de include:spf-x.dfki.de include:spf.protection.outlook.com include:spfa.myconvento.com ~all"60
TXT"adobe-idp-site-verification=267539f8a8a260369b0162359443db47a3d709c51c1552a16db95a29319a2229"60
TXT"MS=8CFBE5FC2F594347D3578EE9B29997E004FDAF0E"60
TXT"google-site-verification=6iKtuyAdMvNDq_EvhxhMP-GXOlSDSjUgkvoDwFjBcGQ"60
TXT"_telesec-domain-validation=2025-02-18_ALjPA1kGxDGUjsm1EtBUeH8aajovKFyPE6vOEtgqcr4yhXaxNp"60
CAA0 issue "sectigo.com"86400
CAA0 issue "harica.gr"86400
CAA0 issue "pki.dfn.de"86400
CAA0 issue "letsencrypt.org"86400
CAA0 issue "telesec.de"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, 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: sectigo.com, harica.gr, pki.dfn.de, letsencrypt.org, telesec.de.