logo.de

Checked 21 October 2026, 23:20 UTC · via 8.8.8.8
!Passed with warnings
19 passed 3 warnings 0 failed 7 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

ns01.zdf.de, ns02.zdf.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns01.zdf.de, ns02.zdf.de
NS in the zone
ns01.zdf.de, ns02.zdf.de
NameserverAddressesNetwork (AS)Glue
ns01.zdf.de194.45.94.1AS43354 ZDF-AS - ZDF Zweites Deutsches Fernsehen, DE194.45.94.1
ns02.zdf.de91.197.28.1AS43354 ZDF-AS - ZDF Zweites Deutsches Fernsehen, DE91.197.28.1

Checks

  • i
    2 nameservers
    Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: ns01.zdf.de, ns02.zdf.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 0 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS43354 (ZDF-AS - ZDF Zweites Deutsches Fernsehen, DE): 2 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

pass

2 of 2 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns01.zdf.de 194.45.94.1NOERROR, 6 ms, authoritativenoyes / yesrefused-
ns02.zdf.de 91.197.28.1NOERROR, 7 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 2 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 39 · primary nmaiz-iblox01.zdf.de

Found

Primary (MNAME)
nmaiz-iblox01.zdf.de
Contact (RNAME)
netzwerk.zdf.de
Serial
39
Refresh / retry
900 s / 300 s
Expire
2592000 s
Negative TTL
180 s

Serial per nameserver

NameserverSerial
ns01.zdf.de (194.45.94.1)39
ns02.zdf.de (91.197.28.1)39

Checks

  • ✓ Serial 39 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    refresh 15m is outside 20m–1d; negative caching TTL (minimum) 3m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 15m, retry 5m, expire 30d, negative TTL 3m.
    #23
  • i
    Hidden master
    The primary nameserver nmaiz-iblox01.zdf.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 netzwerk@zdf.de #25
    The SOA RNAME netzwerk.zdf.de means netzwerk@zdf.de.
  • ✓ Counter serial #26
    The serial 39 is a plain counter.

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

7 records at the apex

Found

Read from
194.45.94.1:53
TypeValueTTL
SOAnmaiz-iblox01.zdf.de. netzwerk.zdf.de. 39 900 300 2592000 1802700
NSns01.zdf.de.2700
NSns02.zdf.de.2700
A91.197.29.492700
TXT"361472fc3851aa01fb10329d9321c020d0ffc108d5094b3fbb6d251b4cad4b5"2700
TXT"_kpdqtx72zvs9unskmfzz2b18yvz6c48"2700
TXT"google-site-verification=TMvWjGd-JcDcwdawPBq4_lpfxdcb_PxVQM8coB-jN-M"2700

Checks

  • ✓ TTLs within range #32
    TTLs: A 45m, NS 45m. The NS TTL at the parent is 1d and in the zone 45m; 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