iass-potsdam.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

deneb.dfn.de, zrt7b.gfz-potsdam.de

Found

Parent zone

de

Delegation from

a.nic.de (194.0.0.53)

NS at the parent

deneb.dfn.de, zrt7b.gfz-potsdam.de

NS in the zone

deneb.dfn.de, zrt7b.gfz-potsdam.de

Checks

• i

  2 nameservers

  Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: deneb.dfn.de, zrt7b.gfz-potsdam.de.

  #6
• ✓ 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 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): 3 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: zrt7b.gfz-potsdam.de.

  #13

3 of 3 addresses answer authoritatively

Found

Checks

• ✓ All respond #14

  All 3 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: deneb.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.