tuebingen.de

Checked 22 October 2026, 00:41 UTC · via 8.8.8.8
!Passed with warnings
21 passed 3 warnings 0 failed 5 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

dns1.belwue.de, dns3.belwue.de, dns5.belwue.de, ns1.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, dns5.belwue.de, ns1.tuebingen.de
NS in the zone
dns1.belwue.de, dns3.belwue.de, dns5.belwue.de, ns1.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
dns5.belwue.de129.143.4.5 2001:7c0::53:5AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE129.143.4.5 2001:7c0::53:5
ns1.tuebingen.de193.197.23.35 2001:7c7:1708:10::2AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE193.197.23.35 2001:7c7:1708::2

Checks

  • ✓ 4 nameservers #6
    Delegated to dns1.belwue.de, dns3.belwue.de, dns5.belwue.de, ns1.tuebingen.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • !
    Glue differs from the zone
    The addresses at the parent (glue) differ from the addresses in the zone: ns1.tuebingen.de (glue 193.197.23.35, 2001:7c7:1708::2, zone 193.197.23.35, 2001:7c7:1708:10::2). Update the glue at your registrar.
    #8
  • ✓ 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 4 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)
dns5.belwue.de 129.143.4.5NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns5.belwue.de 2001:7c0::53:5NOERROR, 7 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
ns1.tuebingen.de 193.197.23.35NOERROR, 8 ms, authoritativenoyes / yesrefused-
ns1.tuebingen.de 2001:7c7:1708:10::2NOERROR, 11 ms, authoritativenoyes / yesrefused-

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)"; dns5.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 2026100601 · primary ns1.tuebingen.de

Found

Primary (MNAME)
ns1.tuebingen.de
Contact (RNAME)
hostmaster.tuebingen.de
Serial
2026100601
Refresh / retry
21600 s / 1800 s
Expire
2419200 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns1.belwue.de (129.143.2.10)2026100601
dns1.belwue.de (2001:7c0::53:10)2026100601
dns3.belwue.de (129.143.253.133)2026100601
dns3.belwue.de (2001:7c0:0:253::133)2026100601
dns5.belwue.de (129.143.4.5)2026100601
dns5.belwue.de (2001:7c0::53:5)2026100601
ns1.tuebingen.de (193.197.23.35)2026100601
ns1.tuebingen.de (2001:7c7:1708:10::2)2026100601

Checks

  • ✓ Serial 2026100601 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 6h, retry 30m, expire 28d, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.tuebingen.de is one of the listed nameservers.
  • ✓ Contact hostmaster@tuebingen.de #25
    The SOA RNAME hostmaster.tuebingen.de means hostmaster@tuebingen.de.
  • ✓ Date-based serial #26
    The serial 2026100601 follows the YYYYMMDDnn convention (2026-10-06).

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

13 records at the apex

Found

Read from
129.143.2.10:53
TypeValueTTL
SOAns1.tuebingen.de. hostmaster.tuebingen.de. 2026100601 21600 1800 2419200 864003600
NSns1.tuebingen.de.86400
NSdns5.belwue.de.86400
NSdns1.belwue.de.86400
NSdns3.belwue.de.86400
A193.197.23.5186400
AAAA2001:7c7:1708::386400
MX10 mx7.kvnbw.de.3600
MX10 mx8.kvnbw.de.3600
MX10 mx6.kvnbw.de.3600
MX10 mx9.kvnbw.de.3600
TXT"google-site-verification=6AMFFUeCeKX3TcI44SsQiftxrsNPHURDpwKm7Sxed9w"86400
TXT"v=spf1 mx include:spf.protect.kvnbw.de " "a:smtpdvd1.kvnbw.de a:smtpdvd2.kvnbw.de include:spf.protection.outlook.com " "include:_spf.belwue.de ip4:193.197.23.36 ip4:159.69.143.158 ip4:94.16.113.42 " "ip4:85.214.133.98 ip6:2a01:4f8:231:25dc::2 a:ferienprogramm-online.de ~all"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 1d, AAAA 1d, MX 1h, 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