dzif.de

Checked 21 October 2026, 22:15 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

ns1.idmkd.uni-frankfurt.de, ns2.idmcd.eu, ns3.idmcd.de, ns4.idmkd.uni-frankfurt.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns1.idmkd.uni-frankfurt.de, ns2.idmcd.eu, ns3.idmcd.de, ns4.idmkd.uni-frankfurt.de
NS in the zone
ns1.idmkd.uni-frankfurt.de, ns2.idmcd.eu, ns3.idmcd.de, ns4.idmkd.uni-frankfurt.de
NameserverAddressesNetwork (AS)Glue
ns1.idmkd.uni-frankfurt.de141.2.148.30 2001:a38:1001:1480:141:2:148:30AS20633 UNIFFM-NET - Johann Wolfgang Goethe-Universitat Frankfurt am Main, DE AS20633 UNIFFM-NET - Johann Wolfgang Goethe-Universitat Frankfurt am Main, DE-
ns2.idmcd.eu195.201.220.211 2a01:4f8:1c1c:bca0::1AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
ns3.idmcd.de116.202.26.118 2a01:4f8:c012:727c::1AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE116.202.26.118 2a01:4f8:c012:727c::1
ns4.idmkd.uni-frankfurt.de141.2.148.31AS20633 UNIFFM-NET - Johann Wolfgang Goethe-Universitat Frankfurt am Main, DE-

Checks

  • ✓ 4 nameservers #6
    Delegated to ns1.idmkd.uni-frankfurt.de, ns2.idmcd.eu, ns3.idmcd.de, ns4.idmkd.uni-frankfurt.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ No glue needed #8
    All nameservers are outside the zone, so no glue records are needed.
  • ✓ 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 3 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS20633 (UNIFFM-NET - Johann Wolfgang Goethe-Universitat Frankfurt am Main, DE): 3 addresses; AS24940 (HETZNER-AS - Hetzner Online GmbH, DE): 4 addresses.
  • ✓ Nameserver names under 2 TLDs #12
    Nameserver names use the TLDs .de, .eu.
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns4.idmkd.uni-frankfurt.de.
    #13

Nameservers

fail

6 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.idmkd.uni-frankfurt.de 141.2.148.30NOERROR, 4 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6
ns1.idmkd.uni-frankfurt.de 2001:a38:1001:1480:141:2:148:30no responsenono / no--
ns2.idmcd.eu 195.201.220.211NOERROR, 3 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6
ns2.idmcd.eu 2a01:4f8:1c1c:bca0::1NOERROR, 2 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6
ns3.idmcd.de 116.202.26.118NOERROR, 6 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6
ns3.idmcd.de 2a01:4f8:c012:727c::1NOERROR, 4 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6
ns4.idmkd.uni-frankfurt.de 141.2.148.31NOERROR, 4 ms, authoritativenoyes / yesrefusedKnot DNS 3.4.6

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns1.idmkd.uni-frankfurt.de (2001:a38:1001:1480:141:2:148:30): read udp [2a01:4f8:1c1c:eebf::1]:44303->[2001:a38:1001:1480:141:2:148:30]: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: ns1.idmkd.uni-frankfurt.de: "Knot DNS 3.4.6"; ns2.idmcd.eu: "Knot DNS 3.4.6"; ns3.idmcd.de: "Knot DNS 3.4.6"; ns4.idmkd.uni-frankfurt.de: "Knot DNS 3.4.6". 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

info

serial 2026083100 · primary ns.dzif.de

Found

Primary (MNAME)
ns.dzif.de
Contact (RNAME)
dnsadmin.dzif.de
Serial
2026083100
Refresh / retry
10800 s / 3600 s
Expire
604800 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
ns1.idmkd.uni-frankfurt.de (141.2.148.30)2026083100
ns2.idmcd.eu (195.201.220.211)2026083100
ns2.idmcd.eu (2a01:4f8:1c1c:bca0::1)2026083100
ns3.idmcd.de (116.202.26.118)2026083100
ns3.idmcd.de (2a01:4f8:c012:727c::1)2026083100
ns4.idmkd.uni-frankfurt.de (141.2.148.31)2026083100

Checks

  • ✓ Serial 2026083100 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 7d, negative TTL 1h.
  • i
    Hidden master
    The primary nameserver ns.dzif.de is not listed as a nameserver: a hidden master that only feeds the public secondaries. That is a common setup; make sure it is not reachable for zone transfers from outside.
    #24
  • ✓ Contact dnsadmin@dzif.de #25
    The SOA RNAME dnsadmin.dzif.de means dnsadmin@dzif.de.
  • ✓ Date-based serial #26
    The serial 2026083100 follows the YYYYMMDDnn convention (2026-08-31).

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

10 records at the apex

Found

Read from
141.2.148.30:53
TypeValueTTL
SOAns.dzif.de. dnsadmin.dzif.de. 2026083100 10800 3600 604800 36003600
NSns1.idmkd.uni-frankfurt.de.3600
NSns2.idmcd.eu.3600
NSns3.idmcd.de.3600
NSns4.idmkd.uni-frankfurt.de.3600
A149.233.9.853600
MX10 mx01.outlook.dehosted.net.3600
MX20 mx02.outlook.dehosted.net.3600
TXT"brevo-code:1db785c3efc8ecbde7a1d927b1cf6f5d"3600
TXT"v=spf1 include:mail.idcohorts.net include:lists.dzif.de include:spf.nl2go.com include:spf.outlook.dehosted.net include:spf1.werk21system.de a:mail2.pluspunkthosting.de ip4:149.233.9.0/25 a -all"3600

Checks

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