zib.de

Checked 22 October 2026, 01:20 UTC · via 8.8.8.8
!Passed with warnings
20 passed 1 warning 0 failed 8 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, dns-3.dfn.de, ns1.zib.de, ns2.zib.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, dns-3.dfn.de, ns1.zib.de, ns2.zib.de
NS in the zone
dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de, ns1.zib.de, ns2.zib.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-
dns-3.dfn.de193.174.75.58 2001:638:d:b103::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
ns1.zib.de130.73.108.108AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE130.73.108.108
ns2.zib.de130.73.108.109AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE130.73.108.109

Checks

  • ✓ 5 nameservers #6
    Delegated to dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de, ns1.zib.de, ns2.zib.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.zib.de, ns2.zib.de.
  • ✓ All names resolve #9
    Every nameserver name has an address and is not an alias.
  • i
    One address family in one network
    all IPv6 addresses are in 2001:638:d::/48, while the other address family is spread over several networks.
    #10
  • 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): 8 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: ns1.zib.de, ns2.zib.de.
    #13

Nameservers

info

8 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 14 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
dns-3.dfn.de 193.174.75.58NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 8 ms, authoritativenoyes / yesrefused0
ns1.zib.de 130.73.108.108NOERROR, 13 ms, authoritativenoyes / yesrefused-
ns2.zib.de 130.73.108.109NOERROR, 13 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 8 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"; dns-3.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 2026102102 · primary ns1.zib.de

Found

Primary (MNAME)
ns1.zib.de
Contact (RNAME)
hostmaster.zib.de
Serial
2026102102
Refresh / retry
43200 s / 3600 s
Expire
3600000 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)2026102102
dns-1.dfn.de (2001:638:d:b101::1)2026102102
dns-2.dfn.de (193.174.75.54)2026102102
dns-2.dfn.de (2001:638:d:b102::1)2026102102
dns-3.dfn.de (193.174.75.58)2026102102
dns-3.dfn.de (2001:638:d:b103::1)2026102102
ns1.zib.de (130.73.108.108)2026102102
ns2.zib.de (130.73.108.109)2026102102

Checks

  • ✓ Serial 2026102102 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 12h, retry 1h, expire 1000h, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.zib.de is one of the listed nameservers.
  • ✓ Contact hostmaster@zib.de #25
    The SOA RNAME hostmaster.zib.de means hostmaster@zib.de.
  • ✓ Date-based serial #26
    The serial 2026102102 follows the YYYYMMDDnn convention (2026-10-21).

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

info

24 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAns1.zib.de. hostmaster.zib.de. 2026102102 43200 3600 3600000 8640086400
NSns2.zib.de.86400
NSdns-1.dfn.de.86400
NSdns-2.dfn.de.86400
NSdns-3.dfn.de.86400
NSns1.zib.de.86400
A130.73.131.15386400
MX20 mailer04.zib.de.86400
MX50 mailer01.zib.de.86400
MX20 mailer01-b.zib.de.86400
MX20 mailer03.zib.de.86400
MX20 mailer01-a.zib.de.86400
TXT"docusign=55832c36-b152-4c4f-bc12-162412938f7e"86400
TXT"ZOOM_verify_dRRBvGdFQy2sH75-9d8NDw"86400
TXT"sophos-domain-verification=09321a0cc8a8848f0f257a0372b779526bcb90b1ee37c1918ba6a67ecbe9666d"86400
TXT"google-site-verification=cwtJ4wQWCKhYf9a7tQ4kw9bfjVbEG8XHLB50ihzgv1g"86400
TXT"HARICA-IrSQwWUKIANWPDCxcVY"86400
TXT"cisco-ci-domain-verification=4b704d9b9771b5f7d71b7740f926f7c312909062e028f45fae976fc5b647e96"86400
TXT"v=spf1 ip4:130.73.108.11 ip4:130.73.108.150 ip4:130.73.108.151 ip4:130.73.108.154 ip4:130.73.108.155 ip4:130.73.108.163 ip4:130.73.108.164 ip4:130.73.108.165 -all"86400
TXT"apple-domain-verification=LyEvvqpC53l48e5z"86400
TXT"google-site-verification=68gILnIEFnHitdvfMggWd8-LoFqCy3wucPNlwkE1guA"86400
TXT"anthropic-domain-verification-0xyara=ngspNjY13vou5M3xRNTZaTgV5"86400
TXT"772c1d28-a168-4fe7-a094-3d8be882f221"86400
TXT"MS=ms98256402"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.
  • i
    No CAA records
    Without CAA records any certificate authority may issue certificates for this domain. A CAA record limits issuance to the CAs you use.
    #35