dkrz.de

Checked 21 October 2026, 22:14 UTC · via 8.8.8.8
!Passed with warnings
26 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

dns-2.dfn.de, ns1.dkrz.de, ns2.dkrz.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-2.dfn.de, ns1.dkrz.de, ns2.dkrz.de
NS in the zone
dns-2.dfn.de, ns1.dkrz.de, ns2.dkrz.de
NameserverAddressesNetwork (AS)Glue
dns-2.dfn.de193.174.75.54 2001:638:d:b102::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
ns1.dkrz.de136.172.11.1 2001:638:70e:10b::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE136.172.11.1 2001:638:70e:10b::1
ns2.dkrz.de136.172.12.1 2001:638:70e:10c::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE136.172.12.1 2001:638:70e:10c::1

Checks

  • ✓ 3 nameservers #6
    Delegated to dns-2.dfn.de, ns1.dkrz.de, ns2.dkrz.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.dkrz.de, ns2.dkrz.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.
  • 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
dns-2.dfn.de 193.174.75.54NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 2001:638:d:b102::1NOERROR, 7 ms, authoritativenoyes / yesrefused0
ns1.dkrz.de 136.172.11.1NOERROR, 13 ms, authoritativenoyes / yesrefused9.16.23-RH
ns1.dkrz.de 2001:638:70e:10b::1NOERROR, 13 ms, authoritativenoyes / yesrefused9.16.23-RH
ns2.dkrz.de 136.172.12.1NOERROR, 13 ms, authoritativenoyes / yesrefused9.16.23-RH
ns2.dkrz.de 2001:638:70e:10c::1NOERROR, 13 ms, authoritativenoyes / yesrefused9.16.23-RH

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: ns1.dkrz.de: "9.16.23-RH"; ns2.dkrz.de: "9.16.23-RH". 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

warn

serial 2026102296 · primary ns1.dkrz.de

Found

Primary (MNAME)
ns1.dkrz.de
Contact (RNAME)
hostmaster.dkrz.de
Serial
2026102296
Refresh / retry
172800 s / 7200 s
Expire
1209600 s
Negative TTL
7200 s

Serial per nameserver

NameserverSerial
dns-2.dfn.de (193.174.75.54)2026102296
dns-2.dfn.de (2001:638:d:b102::1)2026102296
ns1.dkrz.de (136.172.11.1)2026102296
ns1.dkrz.de (2001:638:70e:10b::1)2026102296
ns2.dkrz.de (136.172.12.1)2026102296
ns2.dkrz.de (2001:638:70e:10c::1)2026102296

Checks

  • ✓ Serial 2026102296 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    refresh 2d is outside 20m–1d. Current values: refresh 2d, retry 2h, expire 14d, negative TTL 2h.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.dkrz.de is one of the listed nameservers.
  • ✓ Contact hostmaster@dkrz.de #25
    The SOA RNAME hostmaster.dkrz.de means hostmaster@dkrz.de.
  • ✓ Date-based serial #26
    The serial 2026102296 follows the YYYYMMDDnn convention (2026-10-22).

DNSSEC

info

Signed, DS published at parent

Found

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

DS at the parent

Key tagAlgorithmDigestMatches a key
24041ECDSAP256SHA256 (13)SHA256 E38126DF806C116A…yes

DNSKEY in the zone

Key tagRoleAlgorithm
24041KSK (257)ECDSAP256SHA256 (13)
47898ZSK (256)ECDSAP256SHA256 (13)

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 24041 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • ✓ Signatures valid until 2026-11-02 #30
    The earliest DNSKEY/SOA signature expires at 2026-11-02 06:57 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

14 records at the apex

Found

Read from
193.174.75.54:53
TypeValueTTL
SOAns1.dkrz.de. hostmaster.dkrz.de. 2026102296 172800 7200 1209600 720021600
NSns1.dkrz.de.21600
NSns2.dkrz.de.21600
NSdns-2.dfn.de.21600
A136.172.12.2021600
AAAA2001:638:70e:10c::1421600
MX10 mailin4.dkrz.de.21600
MX10 mailin3.dkrz.de.21600
TXT"v=spf1 +a:mailhost.dkrz.de +a:mailext-ha.dkrz.de -all"21600
TXT"google-site-verification=jhhv8KwxuYH97tJUAzbUyoOGe6F7wJO3UpZ07gwkpdI"21600
TXT"MS=D2B141813E6964B6E56B6DA955395FAB30A90E0F"21600
CAA0 issue "harica.gr"21600
CAA0 issue "sectigo.com"21600
CAA0 issue "pki.dfn.de"21600

Checks

  • ✓ TTLs within range #32
    TTLs: A 6h, AAAA 6h, MX 6h, NS 6h. The NS TTL at the parent is 1d and in the zone 6h; 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, sectigo.com, pki.dfn.de.