aok-bv.de

Checked 21 October 2026, 21:30 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

warn

ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de
NS in the zone
ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.de
NameserverAddressesNetwork (AS)Glue
ns1.aok.de217.110.254.17AS8220 COLT - COLT Technology Services Group Limited, GB217.110.254.17
ns2.aok.de217.110.254.18AS8220 COLT - COLT Technology Services Group Limited, GB217.110.254.18
ns3.aok.de217.111.83.17AS8220 COLT - COLT Technology Services Group Limited, GB217.111.83.17
ns4.aok.de217.111.83.18AS8220 COLT - COLT Technology Services Group Limited, GB217.111.83.18

Checks

  • ✓ 4 nameservers #6
    Delegated to ns1.aok.de, ns2.aok.de, ns3.aok.de, ns4.aok.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 2 IPv4 /24s and 0 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS8220 (COLT - COLT Technology Services Group Limited, GB): 4 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
  • !
    No IPv6
    None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.
    #13

Nameservers

fail

2 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.aok.de 217.110.254.17NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns2.aok.de 217.110.254.18NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns3.aok.de 217.111.83.17no responsenono / no--
ns4.aok.de 217.111.83.18no responsenono / no--

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns3.aok.de (217.111.83.17): read udp 46.225.38.91:42662->217.111.83.17:53: i/o timeout; ns4.aok.de (217.111.83.18): read udp 46.225.38.91:39583->217.111.83.18:53: 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.
  • ✓ No version disclosed #17
    The nameservers don't reveal their software version.
  • ✓ 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

pass

serial 2026093001 · primary ns2.aok.de

Found

Primary (MNAME)
ns2.aok.de
Contact (RNAME)
domain-requests.colt.net
Serial
2026093001
Refresh / retry
10800 s / 3600 s
Expire
604800 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
ns1.aok.de (217.110.254.17)2026093001
ns2.aok.de (217.110.254.18)2026093001

Checks

  • ✓ Serial 2026093001 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 7d, negative TTL 10m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns2.aok.de is one of the listed nameservers.
  • ✓ Contact domain-requests@colt.net #25
    The SOA RNAME domain-requests.colt.net means domain-requests@colt.net.
  • ✓ Date-based serial #26
    The serial 2026093001 follows the YYYYMMDDnn convention (2026-09-30).

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

6 records at the apex

Found

Read from
217.110.254.17:53
TypeValueTTL
SOAns2.aok.de. domain-requests.colt.net. 2026093001 10800 3600 604800 6001800
NSns3.aok.de.1800
NSns2.aok.de.1800
NSns4.aok.de.1800
NSns1.aok.de.1800
A217.110.254.1401800

Checks

  • ✓ TTLs within range #32
    TTLs: A 30m, NS 30m. The NS TTL at the parent is 1d and in the zone 30m; 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