zdf.de

Checked 22 October 2026, 01:10 UTC · via 8.8.8.8
!Passed with warnings
19 passed 4 warnings 0 failed 6 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
a1-107.akam.net, a10-64.akam.net, a11-65.akam.net, a14-66.akam.net, a22-67.akam.net, a9-66.akam.net, ns01.zdf.de, ns02.zdf.de
NameserverAddressesNetwork (AS)Glue
a1-107.akam.net (zone only)193.108.91.107 2600:1401:2::6bAS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a10-64.akam.net (zone only)96.7.50.64 2600:1480:d000::40AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a11-65.akam.net (zone only)84.53.139.65 2600:1480:1::41AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a14-66.akam.net (zone only)184.26.161.66 2600:1480:1800::42AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a22-67.akam.net (zone only)23.211.61.67 2600:1480:7800::43AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a9-66.akam.net (zone only)184.85.248.66 2a02:26f0:117::42AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
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
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only in the zone: a1-107.akam.net, a10-64.akam.net, a11-65.akam.net, a14-66.akam.net, a22-67.akam.net, a9-66.akam.net. a1-107.akam.net, a10-64.akam.net, a11-65.akam.net, a14-66.akam.net, a22-67.akam.net, a9-66.akam.net, ns01.zdf.de, ns02.zdf.de report NS a1-107.akam.net a10-64.akam.net a11-65.akam.net a14-66.akam.net a22-67.akam.net a9-66.akam.net ns01.zdf.de ns02.zdf.de.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: ns01.zdf.de, ns02.zdf.de.
  • ✓ 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 8 IPv4 /24s and 6 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS21342 (AKAMAI-ASN2 - Akamai International B.V., NL): 12 addresses; AS43354 (ZDF-AS - ZDF Zweites Deutsches Fernsehen, DE): 2 addresses.
  • 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
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns01.zdf.de, ns02.zdf.de.
    #13

Nameservers

warn

14 of 14 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
a1-107.akam.net 193.108.91.107NOERROR, 3 ms, authoritativenoyes / yesrefused41824.4
a1-107.akam.net 2600:1401:2::6bNOERROR, 4 ms, authoritativenoyes / yesrefused41824.9
a10-64.akam.net 96.7.50.64NOERROR, 3 ms, authoritativenoyes / yesrefused48878.29
a10-64.akam.net 2600:1480:d000::40NOERROR, 4 ms, authoritativenoyes / yesrefused48878.32
a11-65.akam.net 84.53.139.65NOERROR, 3 ms, authoritativenoyes / yesrefused41824.7
a11-65.akam.net 2600:1480:1::41NOERROR, 4 ms, authoritativenoyes / yesrefused41824.11
a14-66.akam.net 184.26.161.66NOERROR, 4 ms, authoritativenoyes / yesrefused48878.26
a14-66.akam.net 2600:1480:1800::42NOERROR, 4 ms, authoritativenoyes / yesrefused48878.31
a22-67.akam.net 23.211.61.67NOERROR, 4 ms, authoritativenoyes / yesrefused48878.33
a22-67.akam.net 2600:1480:7800::43NOERROR, 4 ms, authoritativenoyes / yesrefused48878.27
a9-66.akam.net 184.85.248.66NOERROR, 4 ms, authoritativenoyes / yesrefused41824.7
a9-66.akam.net 2a02:26f0:117::42NOERROR, 4 ms, authoritativenoyes / yesrefused41824.10
ns01.zdf.de 194.45.94.1NOERROR, 8 ms, authoritativenoyes / yesrefused-
ns02.zdf.de 91.197.28.1NOERROR, 6 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 14 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: a1-107.akam.net: "41824.4"; a1-107.akam.net: "41824.9"; a10-64.akam.net: "48878.29"; a10-64.akam.net: "48878.32"; a11-65.akam.net: "41824.7"; a11-65.akam.net: "41824.11"; a14-66.akam.net: "48878.26"; a14-66.akam.net: "48878.31"; a22-67.akam.net: "48878.33"; a22-67.akam.net: "48878.27"; a9-66.akam.net: "41824.7"; a9-66.akam.net: "41824.10". 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.

SOA

warn

serial 2008116456 · primary ns01.zdf.de

Found

Primary (MNAME)
ns01.zdf.de
Contact (RNAME)
netzwerk.zdf.de
Serial
2008116456
Refresh / retry
900 s / 300 s
Expire
2592000 s
Negative TTL
180 s

Serial per nameserver

NameserverSerial
a1-107.akam.net (193.108.91.107)2008116456
a1-107.akam.net (2600:1401:2::6b)2008116456
a10-64.akam.net (96.7.50.64)2008116456
a10-64.akam.net (2600:1480:d000::40)2008116456
a11-65.akam.net (84.53.139.65)2008116456
a11-65.akam.net (2600:1480:1::41)2008116456
a14-66.akam.net (184.26.161.66)2008116456
a14-66.akam.net (2600:1480:1800::42)2008116456
a22-67.akam.net (23.211.61.67)2008116456
a22-67.akam.net (2600:1480:7800::43)2008116456
a9-66.akam.net (184.85.248.66)2008116456
a9-66.akam.net (2a02:26f0:117::42)2008116456
ns01.zdf.de (194.45.94.1)2008116456
ns02.zdf.de (91.197.28.1)2008116456

Checks

  • ✓ Serial 2008116456 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
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns01.zdf.de is one of the listed nameservers.
  • ✓ Contact netzwerk@zdf.de #25
    The SOA RNAME netzwerk.zdf.de means netzwerk@zdf.de.
  • ✓ Timestamp serial #26
    The serial 2008116456 is a Unix timestamp (2033-08-20 02:07 UTC).

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

22 records at the apex

Found

Read from
193.108.91.107:53
TypeValueTTL
SOAns01.zdf.de. netzwerk.zdf.de. 2008116456 900 300 2592000 1802700
NSa1-107.akam.net.2700
NSa22-67.akam.net.2700
NSa9-66.akam.net.2700
NSa11-65.akam.net.2700
NSns02.zdf.de.2700
NSns01.zdf.de.2700
NSa10-64.akam.net.2700
NSa14-66.akam.net.2700
A91.197.29.78600
MX15 mail.zdf.de.2700
TXT"_kpdqtx72zvs9unskmfzz2b18yvz6c48"2700
TXT"ZOOM_verify_Wllf7UjIfNGKc1zFRX8GZ6"2700
TXT"apple-domain-verification=lVOPviAnVo9tQfOE"2700
TXT"xoW2hdCeCj+Puf8+patUWLK0CADMC7YckkBwGJZkvmbO2Dsz2lqCoLnw6JI6+ql7rA375YHHtyqTkXvABiVKxg=="2700
TXT"v=spf1 include:spf1.zdf.de include:spf.protection.outlook.com include:spf.nl2go.com include:spf.mailjet.com include:spf-005ffa01.pphosted.com -all"2700
TXT"MS=ms99553264"2700
TXT"teamviewer-sso-verification=0a46b98a110a4950a4773ead0ebca2bb"2700
TXT"facebook-domain-verification=hb6wb986e73ua5fwxn6t9zfqjq9olp"2700
TXT"google-site-verification=MOFvgZPijgADlwMs-EP7lm6BTgGVRhkbX5t8BdG61nQ"2700
TXT"0F5FDAA57CC54669BF2D9F3181A7AA1733267250C947FFE163DCC0FD6E518079"2700
TXT"miro-verification=7d15c328d1c85b596fe22b6e31bb66591b1752c3"2700

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, MX 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