dkfz.de

.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

dns1.belwue.de, dns3.belwue.de, ns-ext.inet.dkfz-heidelberg.de

Found

Parent zone

de

Delegation from

a.nic.de (194.0.0.53)

NS at the parent

dns1.belwue.de, dns3.belwue.de, ns-ext.inet.dkfz-heidelberg.de

NS in the zone

dns1.belwue.de, dns3.belwue.de, ns-ext.inet.dkfz-heidelberg.de

Checks

• ✓ 3 nameservers #6

  Delegated to dns1.belwue.de, dns3.belwue.de, ns-ext.inet.dkfz-heidelberg.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.
• i

  One address family in one network

  all IPv6 addresses are in 2001:7c0::/48, while the other address family is spread over several networks.

  #10
• ✓ 2 autonomous systems #11

  The nameservers are spread over: AS553 (BELWUE - Universitaet Stuttgart, DE): 4 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 1 address.
• 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: ns-ext.inet.dkfz-heidelberg.de.

  #13

serial 2026052941 · primary dns-auth.inet.dkfz-heidelberg.de

Found

Primary (MNAME)

dns-auth.inet.dkfz-heidelberg.de

Contact (RNAME)

hostmaster.dkfz.de

Serial

2026052941

Refresh / retry

10800 s / 3600 s

Expire

2419200 s

Negative TTL

900 s

Serial per nameserver

Checks

• ✓ Serial 2026052941 everywhere #22

  All nameservers serve the same version of the zone.
• ✓ Timers within recommendations #23

  SOA refresh 3h, retry 1h, expire 28d, negative TTL 15m.
• i

  Hidden master (not resolvable)

  The primary nameserver dns-auth.inet.dkfz-heidelberg.de is not listed as a nameserver and does not resolve publicly: a hidden master, or a placeholder name. Some tools (e.g. dynamic updates) use MNAME to find the primary.

  #24
• ✓ Contact hostmaster@dkfz.de #25

  The SOA RNAME hostmaster.dkfz.de means hostmaster@dkfz.de.
• ✓ Date-based serial #26

  The serial 2026052941 follows the YYYYMMDDnn convention (2026-05-29).