ixtheo.de

Checked 21 October 2026, 23:00 UTC · via 8.8.8.8
!Passed with warnings
21 passed 2 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

info

dns1.belwue.de, dns3.belwue.de, dns3.uni-tuebingen.de, dns4.uni-tuebingen.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns1.belwue.de, dns3.belwue.de, dns3.uni-tuebingen.de, dns4.uni-tuebingen.de
NS in the zone
dns1.belwue.de, dns3.belwue.de, dns3.uni-tuebingen.de, dns4.uni-tuebingen.de
NameserverAddressesNetwork (AS)Glue
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
dns3.uni-tuebingen.de134.2.200.3 2001:7c0:300c:137::8602:c803AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE134.2.200.3 2001:7c0:300c:137::8602:c803
dns4.uni-tuebingen.de134.2.200.4 2001:7c0:300c:137::8602:c804AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE134.2.200.4 2001:7c0:300c:137::8602:c804

Checks

  • ✓ 4 nameservers #6
    Delegated to dns1.belwue.de, dns3.belwue.de, dns3.uni-tuebingen.de, dns4.uni-tuebingen.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 3 IPv4 /24s and 2 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS553 (BELWUE - Universitaet Stuttgart, DE): 8 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
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

warn

8 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
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)
dns3.uni-tuebingen.de 134.2.200.3NOERROR, 10 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.24.04.8-Ubuntu
dns3.uni-tuebingen.de 2001:7c0:300c:137::8602:c803NOERROR, 10 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.24.04.8-Ubuntu
dns4.uni-tuebingen.de 134.2.200.4NOERROR, 10 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.24.04.8-Ubuntu
dns4.uni-tuebingen.de 2001:7c0:300c:137::8602:c804NOERROR, 12 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.24.04.8-Ubuntu

Checks

  • ✓ All respond #14
    All 8 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: 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)"; dns3.uni-tuebingen.de: "9.18.39-0ubuntu0.24.04.8-Ubuntu"; dns4.uni-tuebingen.de: "9.18.39-0ubuntu0.24.04.8-Ubuntu". 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

info

serial 47 · primary dns6.uni-tuebingen.de

Found

Primary (MNAME)
dns6.uni-tuebingen.de
Contact (RNAME)
hostmaster.uni-tuebingen.de
Serial
47
Refresh / retry
21600 s / 1800 s
Expire
3600000 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns1.belwue.de (129.143.2.10)47
dns1.belwue.de (2001:7c0::53:10)47
dns3.belwue.de (129.143.253.133)47
dns3.belwue.de (2001:7c0:0:253::133)47
dns3.uni-tuebingen.de (134.2.200.3)47
dns3.uni-tuebingen.de (2001:7c0:300c:137::8602:c803)47
dns4.uni-tuebingen.de (134.2.200.4)47
dns4.uni-tuebingen.de (2001:7c0:300c:137::8602:c804)47

Checks

  • ✓ Serial 47 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 6h, retry 30m, expire 1000h, negative TTL 1d.
  • i
    Hidden master
    The primary nameserver dns6.uni-tuebingen.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 hostmaster@uni-tuebingen.de #25
    The SOA RNAME hostmaster.uni-tuebingen.de means hostmaster@uni-tuebingen.de.
  • ✓ Counter serial #26
    The serial 47 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

6 records at the apex

Found

Read from
129.143.2.10:53
TypeValueTTL
SOAdns6.uni-tuebingen.de. hostmaster.uni-tuebingen.de. 47 21600 1800 3600000 8640086400
NSdns4.uni-tuebingen.de.3600
NSdns3.belwue.de.3600
NSdns3.uni-tuebingen.de.3600
NSdns1.belwue.de.3600
A134.2.5.11186400

Checks

  • ✓ TTLs within range #32
    TTLs: A 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