clever-tanken.de

ns1.s-42.net, ns2.s-42.net, ns3.s-42.net, ns4.s-42.net

Found

Parent zone

de

Delegation from

a.nic.de (194.0.0.53)

NS at the parent

ns1.s-42.net, ns2.s-42.net, ns3.s-42.net, ns4.s-42.net

NS in the zone

ns1.s-42.net, ns2.s-42.net, ns3.s-42.net, ns4.s-42.net

Checks

• ✓ 4 nameservers #6

  Delegated to ns1.s-42.net, ns2.s-42.net, ns3.s-42.net, ns4.s-42.net.
• ✓ 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 4 IPv4 /24s and 0 IPv6 /48s.
• ✓ 3 autonomous systems #11

  The nameservers are spread over: AS12813 (WORNET-AS - WorNet AG, DE): 2 addresses; AS16276 (OVH - OVH SAS, FR): 1 address; AS50629 (LWLCOM - LWLcom GmbH, DE): 1 address.
• i

  All nameserver names under .net

  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
• !

  No IPv6

  None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.

  #13

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.
• !

  Software version disclosed

  These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns1.s-42.net: "9.18.39-0ubuntu0.22.04.7-Ubuntu"; ns2.s-42.net: "9.18.39-0ubuntu0.24.04.8-Ubuntu"; ns3.s-42.net: "9.18.39-0ubuntu0.22.04.7-Ubuntu"; ns4.s-42.net: "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.

serial 2026101901 · primary ns.wor.net

Found

Primary (MNAME)

ns.wor.net

Contact (RNAME)

admin.wor.de

Serial

2026101901

Refresh / retry

10800 s / 3600 s

Expire

604800 s

Negative TTL

60 s

Serial per nameserver

Checks

• ✓ Serial 2026101901 everywhere #22

  All nameservers serve the same version of the zone.
• !

  Unusual SOA timers

  negative caching TTL (minimum) 1m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 3h, retry 1h, expire 7d, negative TTL 1m.

  #23
• i

  Hidden master

  The primary nameserver ns.wor.net 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 admin@wor.de #25

  The SOA RNAME admin.wor.de means admin@wor.de.
• ✓ Date-based serial #26

  The serial 2026101901 follows the YYYYMMDDnn convention (2026-10-19).

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

10 records at the apex

Found

Read from

212.11.240.69:53

Checks

• !

  Very low TTLs

  These records have a TTL below 5m, causing extra queries and slower lookups: A (1m). Low TTLs are useful just before a planned change. The NS TTL at the parent is 1d and in the zone 5m; resolvers may use either.

  #32
• ✓ 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