bielefeld.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

pns.dtag.de, secondary004.dtag.net

Found

Parent zone

de

Delegation from

a.nic.de (194.0.0.53)

NS at the parent

pns.dtag.de, secondary004.dtag.net

NS in the zone

pns.dtag.de, secondary004.dtag.net

Checks

• i

  2 nameservers

  Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: pns.dtag.de, secondary004.dtag.net.

  #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 2 IPv6 /48s.
• ✓ 2 autonomous systems #11

  The nameservers are spread over: AS3320 (DTAG - Deutsche Telekom AG, DE): 2 addresses; AS5605 (NETUSE - NetUSE AG, DE): 2 addresses.
• ✓ Nameserver names under 2 TLDs #12

  Nameserver names use the TLDs .de, .net.
• ✓ All reachable over IPv6 #13

  Every nameserver has an IPv6 address.

4 of 4 addresses answer authoritatively

Found

Checks

• ✓ All respond #14

  All 4 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: pns.dtag.de: "DomainNameServer"; secondary004.dtag.net: "DomainNameServer".

  #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.

serial 2026102102 · primary ns1.duesseldorf.rz-betrieb.de

Found

Primary (MNAME)

ns1.duesseldorf.rz-betrieb.de

Contact (RNAME)

hostmaster.duesseldorf.rz-betrieb.de

Serial

2026102102

Refresh / retry

10800 s / 3600 s

Expire

604800 s

Negative TTL

86400 s

Serial per nameserver

Checks

• ✓ Serial 2026102102 everywhere #22

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

  SOA refresh 3h, retry 1h, expire 7d, negative TTL 1d.
• i

  Hidden master

  The primary nameserver ns1.duesseldorf.rz-betrieb.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 hostmaster@duesseldorf.rz-betrieb.de #25

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

  The serial 2026102102 follows the YYYYMMDDnn convention (2026-10-21).

12 records at the apex

Found

Read from

194.25.0.125:53

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