limburg.de

Checked 21 October 2026, 23:12 UTC · via 8.8.8.8
!Passed with warnings
23 passed 2 warnings 0 failed 4 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

info

ns-a.ktk.de, ns-b.ktk.io, ns-c.ktk.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns-a.ktk.de, ns-b.ktk.io, ns-c.ktk.de
NS in the zone
ns-a.ktk.de, ns-b.ktk.io, ns-c.ktk.de
NameserverAddressesNetwork (AS)Glue
ns-a.ktk.de212.7.160.5 2a02:1628:0:c000::3:5AS12360 KTK - KEVAG Telekom GmbH, DE AS12360 KTK - KEVAG Telekom GmbH, DE212.7.160.5 2a02:1628:0:c000::3:5
ns-b.ktk.io217.17.16.165 2a01:5580:154::165AS12360 KTK - KEVAG Telekom GmbH, DE AS12360 KTK - KEVAG Telekom GmbH, DE-
ns-c.ktk.de212.7.160.11 2a02:1628:0:c000::3:11AS12360 KTK - KEVAG Telekom GmbH, DE AS12360 KTK - KEVAG Telekom GmbH, DE212.7.160.11 2a02:1628:0:c000::3:11

Checks

  • ✓ 3 nameservers #6
    Delegated to ns-a.ktk.de, ns-b.ktk.io, ns-c.ktk.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 2 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS12360 (KTK - KEVAG Telekom GmbH, DE): 6 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.
    #11
  • ✓ Nameserver names under 2 TLDs #12
    Nameserver names use the TLDs .de, .io.
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

pass

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns-a.ktk.de 212.7.160.5NOERROR, 6 ms, authoritativenoyes / yesrefused-
ns-a.ktk.de 2a02:1628:0:c000::3:5NOERROR, 6 ms, authoritativenoyes / yesrefused-
ns-b.ktk.io 217.17.16.165NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns-b.ktk.io 2a01:5580:154::165NOERROR, 5 ms, authoritativenoyes / yesrefused-
ns-c.ktk.de 212.7.160.11NOERROR, 6 ms, authoritativenoyes / yesrefused-
ns-c.ktk.de 2a02:1628:0:c000::3:11NOERROR, 6 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 6 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.
  • ✓ 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

warn

serial 2025120826 · primary ns-a.ktk.de

Found

Primary (MNAME)
ns-a.ktk.de
Contact (RNAME)
hostmaster.noc.ktk.de
Serial
2025120826
Refresh / retry
86400 s / 3600 s
Expire
86400 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
ns-a.ktk.de (212.7.160.5)2025120826
ns-a.ktk.de (2a02:1628:0:c000::3:5)2025120826
ns-b.ktk.io (217.17.16.165)2025120826
ns-b.ktk.io (2a01:5580:154::165)2025120826
ns-c.ktk.de (212.7.160.11)2025120826
ns-c.ktk.de (2a02:1628:0:c000::3:11)2025120826

Checks

  • ✓ Serial 2025120826 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    expire 1d is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 1d must be longer than refresh + retry. Current values: refresh 1d, retry 1h, expire 1d, negative TTL 1h.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns-a.ktk.de is one of the listed nameservers.
  • ✓ Contact hostmaster@noc.ktk.de #25
    The SOA RNAME hostmaster.noc.ktk.de means hostmaster@noc.ktk.de.
  • ✓ Date-based serial #26
    The serial 2025120826 follows the YYYYMMDDnn convention (2025-12-08).

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

9 records at the apex

Found

Read from
212.7.160.5:53
TypeValueTTL
SOAns-a.ktk.de. hostmaster.noc.ktk.de. 2025120826 86400 3600 86400 36003600
NSns-c.ktk.de.3600
NSns-a.ktk.de.3600
NSns-b.ktk.io.3600
A213.178.84.2093600
MX0 mxa-0099bc01.gslb.pphosted.com.86400
MX0 mxb-0099bc01.gslb.pphosted.com.86400
TXT"v=spf1 ip4:213.178.85.11 -all"3600
TXT"adobe-idp-site-verification=e6d7f1f2bf41f501e428483f1ee170051964eb12cfa7c43b6877c7c4409cdf54"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 1h, MX 1d, 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