zkm.de

Checked 22 October 2026, 01:20 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

dns.zkm.de, dns1.belwue.de, dns3.belwue.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns.zkm.de, dns1.belwue.de, dns3.belwue.de
NS in the zone
dns.zkm.de, dns1.belwue.de, dns3.belwue.de, infoblox.zkm.de
NameserverAddressesNetwork (AS)Glue
dns.zkm.de193.197.172.2AS553 BELWUE - Universitaet Stuttgart, DE193.197.172.2
dns1.belwue.de129.143.2.10 2001:7c0::53:10AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE129.143.2.10 2001:7c0::53:10
dns3.belwue.de129.143.253.133 2001:7c0:0:253::133AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE129.143.253.133 2001:7c0:0:253::133
infoblox.zkm.de (zone only)193.197.168.39AS553 BELWUE - Universitaet Stuttgart, DE-

Checks

  • ✓ 3 nameservers #6
    Delegated to dns.zkm.de, dns1.belwue.de, dns3.belwue.de.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only in the zone: infoblox.zkm.de. dns.zkm.de, dns1.belwue.de, dns3.belwue.de, infoblox.zkm.de report NS dns.zkm.de dns1.belwue.de dns3.belwue.de infoblox.zkm.de.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: dns.zkm.de.
  • ✓ All names resolve #9
    Every nameserver name has an address and is not an alias.
  • i
    One address family in one network
    all IPv6 addresses are in 2001:7c0::/48, while the other address family is spread over several networks.
    #10
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS553 (BELWUE - Universitaet Stuttgart, 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
  • 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: dns.zkm.de, infoblox.zkm.de.
    #13

Nameservers

warn

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns.zkm.de 193.197.172.2NOERROR, 8 ms, authoritativenoyes / yesrefused9.7.3
dns1.belwue.de 129.143.2.10NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns1.belwue.de 2001:7c0::53:10NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns3.belwue.de 129.143.253.133NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns3.belwue.de 2001:7c0:0:253::133NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
infoblox.zkm.de 193.197.168.39NOERROR, 8 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.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: dns.zkm.de: "9.7.3"; dns1.belwue.de: "PowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)"; dns3.belwue.de: "PowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)". 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

pass

serial 2022114874 · primary infoblox.zkm.de

Found

Primary (MNAME)
infoblox.zkm.de
Contact (RNAME)
hostmaster.zkm.de
Serial
2022114874
Refresh / retry
10800 s / 3600 s
Expire
2419200 s
Negative TTL
900 s

Serial per nameserver

NameserverSerial
dns.zkm.de (193.197.172.2)2022114874
dns1.belwue.de (129.143.2.10)2022114874
dns1.belwue.de (2001:7c0::53:10)2022114874
dns3.belwue.de (129.143.253.133)2022114874
dns3.belwue.de (2001:7c0:0:253::133)2022114874
infoblox.zkm.de (193.197.168.39)2022114874

Checks

  • ✓ Serial 2022114874 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 28d, negative TTL 15m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver infoblox.zkm.de is one of the listed nameservers.
  • ✓ Contact hostmaster@zkm.de #25
    The SOA RNAME hostmaster.zkm.de means hostmaster@zkm.de.
  • ✓ Timestamp serial #26
    The serial 2022114874 is a Unix timestamp (2034-01-29 02:34 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

15 records at the apex

Found

Read from
193.197.172.2:53
TypeValueTTL
SOAinfoblox.zkm.de. hostmaster.zkm.de. 2022114874 10800 3600 2419200 90028800
NSdns3.belwue.de.28800
NSdns.zkm.de.28800
NSdns1.belwue.de.28800
NSinfoblox.zkm.de.28800
A193.197.168.18828800
MX30 a1431.mx.srv.dfn.de.900
MX30 b1431.mx.srv.dfn.de.900
MX30 c1431.mx.srv.dfn.de.900
MX20 fortimail.zkm.de.900
TXT"apple-domain-verification=cAkT3PrPl281VWdI"3600
TXT"MS=1F9BB01B154646B5186604944BC94D97825075D8"3600
TXT"bw=uqDW9nAlzCDNMWAcBdwFxqxDG8NQwsy8XYnJky3DDDSz"3600
TXT"google-site-verification=dfBtFSTRo66eUH0dc-sNg4bgbntbz6XMYMtltsq0VNk"3600
TXT"v=spf1 ip4:193.197.168.0/22 ip4:193.197.172.0/24 ip4:54.246.220.150 ip4:54.246.224.90 ip4:208.91.114.151 include:_spf.rexx-suite.com include:mailgun.org ~all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 8h, MX 15m, NS 8h. The NS TTL at the parent is 1d and in the zone 8h; 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