tiho-hannover.de

Checked 22 October 2026, 00:40 UTC · via 8.8.8.8
✗Problems found
21 passed 2 warnings 1 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.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-2.dfn.de, ns1.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.de
NS in the zone
dns-2.dfn.de, ns1.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.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.tiho-hannover.de193.16.4.1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.16.4.1
ns2.tiho-hannover.de193.16.4.8AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.16.4.8
ns3.tiho-hannover.de193.16.4.14AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.16.4.14

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-2.dfn.de, ns1.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.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.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.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 1 IPv6 /48.
  • 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): 5 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.tiho-hannover.de, ns2.tiho-hannover.de, ns3.tiho-hannover.de.
    #13

Nameservers

fail

4 of 5 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.tiho-hannover.de 193.16.4.1no responsenono / no--
ns2.tiho-hannover.de 193.16.4.8NOERROR, 19 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.22.04.7-Ubuntu
ns3.tiho-hannover.de 193.16.4.14NOERROR, 19 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.22.04.7-Ubuntu

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns1.tiho-hannover.de (193.16.4.1): read udp 46.225.38.91:56719->193.16.4.1:53: i/o timeout.
    #14
  • ✓ 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: ns2.tiho-hannover.de: "9.18.39-0ubuntu0.22.04.7-Ubuntu"; ns3.tiho-hannover.de: "9.18.39-0ubuntu0.22.04.7-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 1832 · primary ns2.tiho-hannover.de

Found

Primary (MNAME)
ns2.tiho-hannover.de
Contact (RNAME)
hotline.tiho-hannover.de
Serial
1832
Refresh / retry
18000 s / 3600 s
Expire
604800 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
dns-2.dfn.de (193.174.75.54)1832
dns-2.dfn.de (2001:638:d:b102::1)1832
ns2.tiho-hannover.de (193.16.4.8)1832
ns3.tiho-hannover.de (193.16.4.14)1832

Checks

  • ✓ Serial 1832 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 5h, retry 1h, expire 7d, negative TTL 10m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns2.tiho-hannover.de is one of the listed nameservers.
  • ✓ Contact hotline@tiho-hannover.de #25
    The SOA RNAME hotline.tiho-hannover.de means hotline@tiho-hannover.de.
  • ✓ Counter serial #26
    The serial 1832 is a plain counter.

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

16 records at the apex

Found

Read from
193.174.75.54:53
TypeValueTTL
SOAns2.tiho-hannover.de. hotline.tiho-hannover.de. 1832 18000 3600 604800 60010801
NSns1.tiho-hannover.de.10801
NSns3.tiho-hannover.de.10801
NSns2.tiho-hannover.de.10801
NSdns-2.dfn.de.10801
A193.16.4.21110801
MX10 a1401.mx.srv.dfn.de.10801
MX10 c1401.mx.srv.dfn.de.10801
MX10 b1401.mx.srv.dfn.de.10801
TXT"apple-domain-verification=i4gXP8qvkLAs47OG"10801
TXT"v=spf1 ip4:193.16.4.66 ip4:193.16.4.67 a:inets1.gbv.de a:mailgate.tib.eu a:imailer.gwdg.de include:spf.uni-hannover.de include:_spf.b-ite.com include:spf.protection.outlook.com include:_spf.o140.mx.srv.dfn.de -all"10801
TXT"anthropic-domain-verification-f17wtt=VH8pTV2NRcd7d3tXtV0FXb4nJ"10801
TXT"openai-domain-verification=dv-0HTjQoldkUT8FhoJtUEwA56J"10801
CAA0 issue "harica.gr"10801
CAA0 issuewild ";"10801
CAA0 issue "pki.dfn.de"10801

Checks

  • ✓ TTLs within range #32
    TTLs: A 3h0m1s, MX 3h0m1s, NS 3h0m1s. The NS TTL at the parent is 1d and in the zone 3h0m1s; 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, none (issuance forbidden), pki.dfn.de.