helmholtz-hzi.de

Checked 21 October 2026, 22:50 UTC · via 8.8.8.8
!Passed with warnings
23 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

dns-1.dfn.de, dns-2.dfn.de, dns01.helmholtz-hzi.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns-2.dfn.de, dns01.helmholtz-hzi.de
NS in the zone
dns-1.dfn.de, dns-2.dfn.de, dns01.helmholtz-hzi.de
NameserverAddressesNetwork (AS)Glue
dns-1.dfn.de193.174.75.50 2001:638:d:b101::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
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-
dns01.helmholtz-hzi.de193.175.244.7 2001:638:612:1::7AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.244.7 2001:638:612:1::7

Checks

  • ✓ 3 nameservers #6
    Delegated to dns-1.dfn.de, dns-2.dfn.de, dns01.helmholtz-hzi.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: dns01.helmholtz-hzi.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 2 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

info

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 13 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 13 ms, authoritativenoyes / yesrefused0
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
dns01.helmholtz-hzi.de 193.175.244.7NOERROR, 10 ms, authoritativenoyes / yesrefused-
dns01.helmholtz-hzi.de 2001:638:612:1::7NOERROR, 10 ms, authoritativenoyes / yesrefused-

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.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: dns-1.dfn.de: "0"; dns-2.dfn.de: "0".
    #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 2026092401 · primary dns01.helmholtz-hzi.de

Found

Primary (MNAME)
dns01.helmholtz-hzi.de
Contact (RNAME)
hostmaster.helmholtz-hzi.de
Serial
2026092401
Refresh / retry
3600 s / 1800 s
Expire
604800 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)2026092401
dns-1.dfn.de (2001:638:d:b101::1)2026092401
dns-2.dfn.de (193.174.75.54)2026092401
dns-2.dfn.de (2001:638:d:b102::1)2026092401
dns01.helmholtz-hzi.de (193.175.244.7)2026092401
dns01.helmholtz-hzi.de (2001:638:612:1::7)2026092401

Checks

  • ✓ Serial 2026092401 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 30m, expire 7d, negative TTL 10m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns01.helmholtz-hzi.de is one of the listed nameservers.
  • ✓ Contact hostmaster@helmholtz-hzi.de #25
    The SOA RNAME hostmaster.helmholtz-hzi.de means hostmaster@helmholtz-hzi.de.
  • ✓ Date-based serial #26
    The serial 2026092401 follows the YYYYMMDDnn convention (2026-09-24).

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

17 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAdns01.helmholtz-hzi.de. hostmaster.helmholtz-hzi.de. 2026092401 3600 1800 604800 60086400
NSdns01.helmholtz-hzi.de.259200
NSdns-1.dfn.de.259200
NSdns-2.dfn.de.259200
A46.20.39.9386400
MX5 fm.helmholtz-hzi.de.3600
TXT"_telesec-domain-validation=353671_2025-10-20_rKMDBMjQZrkDHyqSLcXEYVxo4wcjy3JnC9gPKhHIEV35lckmHG"3600
TXT"HARICA-zwFskbHEAKg9f9boi5b"3600
TXT"v=spf1 " "ip6:2001:638:612:1::181 ip6:2001:638:612:1::180 " "ip6:2a01:488:42:1000:b24d:6f5b:: " "ip4:193.175.244.0/24 " "ip4:178.77.111.91 " "ip4:159.69.102.144 " "ip4:80.67.29.31 " "ip4:46.20.39.93 " "a:fias.uni-frankfurt.de " "include:_spf-e.cegedim.fr include:_spf-i.cegedim.fr " "include:_spf.o164.mx.srv.dfn.de " "include:_spf-dc55.sapsf.eu " "include:_spf.o117.mx.srv.dfn.de -all"3600
TXT"_telesec-domain-validation=340845_2024-11-21_SPlRGaWFs7Khq4CSwNl5ncGnEpBqnT9o7QZ4yMhBp5Y00hXSRp"3600
TXT"_telesec-domain-validation=2023-10-10_TYsUktWb6lMYFteKmMYhwuXpSByYUfVhdFdCiAc9caxCIJTdk2"3600
TXT"langdock-verify=m1bebAzsoKnaK6CmBwCyrZjeo6xgXQs62qU0mk7CqrI"3600
TXT"_telesec-domain-validation=2023-10-10_faRRtxM8WSJOGtBqT9nmkvilekVIKQogBfvVsHm0R6vYJdPJoj"3600
TXT"Khk0pl6vtW+47aSRhtgcGK84OOAYoHUY8HuOtpOXCv0bhnc+zh3Vu9B5XXVP+jAG6fwX+9zJIC2/A+MqLFe/og=="3600
TXT"adobe-idp-site-verification=31d7093bbbac0254bf74ca889834cac08fe40c675b6c23b92b2f116f902ae9da"3600
TXT"successfactors-site-verification=ZmM4NTcwNTkzMjRiNTIwNWM0NzAyOTg0MGMyZmUyZmRmODJkZTUyYmMxNTUxYmQzMDk0YTEwNGY5NDNlNzk2Yw=="3600
CAA0 issue "harica.gr"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 1d, MX 1h, NS 3d. The NS TTL at the parent is 1d and in the zone 3d; 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.