duesseldorf.de

Checked 21 October 2026, 22:15 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.itk-rheinland.de, ns2nd.itk-rheinland.de, pns.dtag.de, secondary006.dtag.net

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns.itk-rheinland.de, ns2nd.itk-rheinland.de, pns.dtag.de, secondary006.dtag.net
NS in the zone
ns.itk-rheinland.de, ns2nd.itk-rheinland.de, pns.dtag.de, secondary006.dtag.net
NameserverAddressesNetwork (AS)Glue
ns.itk-rheinland.de193.27.22.45AS210849 ITK-RHEINLAND - ITK Rheinland, DE193.27.22.45
ns2nd.itk-rheinland.de193.27.22.46AS210849 ITK-RHEINLAND - ITK Rheinland, DE193.27.22.46
pns.dtag.de194.25.0.125 2003:40:8000::100AS3320 DTAG - Deutsche Telekom AG, DE AS3320 DTAG - Deutsche Telekom AG, DE194.25.0.125 2003:40:8000::100
secondary006.dtag.net195.244.245.25 2a00:fa8:3:0:100:0:6:1AS5605 NETUSE - NetUSE AG, DE AS5605 NETUSE - NetUSE AG, DE-

Checks

  • ✓ 4 nameservers #6
    Delegated to ns.itk-rheinland.de, ns2nd.itk-rheinland.de, pns.dtag.de, secondary006.dtag.net.
  • ✓ 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 3 IPv4 /24s and 2 IPv6 /48s.
  • ✓ 3 autonomous systems #11
    The nameservers are spread over: AS210849 (ITK-RHEINLAND - ITK Rheinland, DE): 2 addresses; AS3320 (DTAG - Deutsche Telekom AG, DE): 2 addresses; AS5605 (NETUSE - NetUSE AG, DE): 2 addresses.
  • ✓ Nameserver names under 2 TLDs #12
    Nameserver names use the TLDs .de, .net.
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns.itk-rheinland.de, ns2nd.itk-rheinland.de.
    #13

Nameservers

warn

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns.itk-rheinland.de 193.27.22.45NOERROR, 8 ms, authoritativenoyes / yesrefused9.18.33
ns2nd.itk-rheinland.de 193.27.22.46NOERROR, 8 ms, authoritativenoyes / yesrefused9.20.23
pns.dtag.de 194.25.0.125NOERROR, 10 ms, authoritativenoyes / yesrefusedDomainNameServer
pns.dtag.de 2003:40:8000::100NOERROR, 7 ms, authoritativenoyes / yesrefusedDomainNameServer
secondary006.dtag.net 195.244.245.25NOERROR, 12 ms, authoritativenoyes / yesrefusedDomainNameServer
secondary006.dtag.net 2a00:fa8:3:0:100:0:6:1NOERROR, 16 ms, authoritativenoyes / yesrefusedDomainNameServer

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: ns.itk-rheinland.de: "9.18.33"; ns2nd.itk-rheinland.de: "9.20.23". 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 2970831966 · primary ns.itk-rheinland.de

Found

Primary (MNAME)
ns.itk-rheinland.de
Contact (RNAME)
postmaster.duesseldorf.de
Serial
2970831966
Refresh / retry
10800 s / 1800 s
Expire
1209600 s
Negative TTL
43200 s

Serial per nameserver

NameserverSerial
ns.itk-rheinland.de (193.27.22.45)2970831966
ns2nd.itk-rheinland.de (193.27.22.46)2970831966
pns.dtag.de (194.25.0.125)2970831966
pns.dtag.de (2003:40:8000::100)2970831966
secondary006.dtag.net (195.244.245.25)2970831966
secondary006.dtag.net (2a00:fa8:3:0:100:0:6:1)2970831966

Checks

  • ✓ Serial 2970831966 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 30m, expire 14d, negative TTL 12h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns.itk-rheinland.de is one of the listed nameservers.
  • ✓ Contact postmaster@duesseldorf.de #25
    The SOA RNAME postmaster.duesseldorf.de means postmaster@duesseldorf.de.
  • ✓ Timestamp serial #26
    The serial 2970831966 is a Unix timestamp (2064-02-21 15:06 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

18 records at the apex

Found

Read from
193.27.22.45:53
TypeValueTTL
SOAns.itk-rheinland.de. postmaster.duesseldorf.de. 2970831966 10800 1800 1209600 4320086400
NSns2nd.itk-rheinland.de.86400
NSpns.dtag.de.86400
NSsecondary006.dtag.net.86400
NSns.itk-rheinland.de.86400
A193.27.22.39600
MX10 mail42.itk-rheinland.de.86400
MX10 mail52.itk-rheinland.de.86400
MX10 mail32.itk-rheinland.de.86400
TXT"duo_sso_verification=czynCNZY0ovlVO3RPTiG7JiC6n7vhsENRiJj6MgjBYNa5PWPs9EdNM2yPiojoNB4"600
TXT"v=spf1 ip4:193.27.22.88 include:_spf.rexx-suite.com ~all"600
TXT"_telesec-domain-validation=355711_2026-02-17_HOBZSv0WZCjaQTJR4gu9vECFLZaL4swbj2sTW44ZsbWZTlQOKq"600
TXT"adobe-idp-site-verification=eac65759811f2b1acc9701456fdef56dc0b95bdb81d03d0f4c9e73d353f6efc6"600
TXT"QuoVadis=759f41f9-090e-48ff-9994-747c8be8ef3b"600
TXT"MS=ms33609169"600
TXT"hibp-verify=dweb_obg9bbvpqdxzouvngiwn4hb1"600
TXT"D-TRUST=X5H2LIPJYVCJAOJJI5E5JRE"600
TXT"google-site-verification=H3C7cO-eVuY249hCd_vjCugwMnKD98oAdgYOnoiMGVw"600

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, MX 1d, NS 1d.
  • ✓ 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