abk-stuttgart.de

Checked 21 October 2026, 21:27 UTC · via 8.8.8.8
✗Problems found
21 passed 3 warnings 1 failed 8 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, rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns1.belwue.de, dns3.belwue.de, rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.de
NS in the zone
dns1.belwue.de, dns3.belwue.de, rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.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
rz-s-dns-ma.abk-stuttgart.de193.197.154.14AS553 BELWUE - Universitaet Stuttgart, DE193.197.154.14
rz-s-dns-sl.abk-stuttgart.de193.197.154.16AS553 BELWUE - Universitaet Stuttgart, DE193.197.154.16

Checks

  • ✓ 4 nameservers #6
    Delegated to dns1.belwue.de, dns3.belwue.de, rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.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: rz-s-dns-ma.abk-stuttgart.de, rz-s-dns-sl.abk-stuttgart.de.
    #13

Nameservers

fail

6 of 6 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)
rz-s-dns-ma.abk-stuttgart.de 193.197.154.14NOERROR, 7 ms, authoritativenoyes / yesrefused-
rz-s-dns-sl.abk-stuttgart.de 193.197.154.16NOERROR, 7 ms, authoritativenoyes / yesALLOWED (780 records)-

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: 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 transfer allowed
    These nameservers send the complete zone to anyone who asks (AXFR), exposing all host names: rz-s-dns-sl.abk-stuttgart.de (193.197.154.16): 780 records. Restrict zone transfers to your secondary servers.
    #18
  • ✓ 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 23067962 · primary rz-s-dns-ma.abk-stuttgart.de

Found

Primary (MNAME)
rz-s-dns-ma.abk-stuttgart.de
Contact (RNAME)
hostmaster.abk-stuttgart.de
Serial
23067962
Refresh / retry
3600 s / 600 s
Expire
1209600 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
dns1.belwue.de (129.143.2.10)23067962
dns1.belwue.de (2001:7c0::53:10)23067962
dns3.belwue.de (129.143.253.133)23067962
dns3.belwue.de (2001:7c0:0:253::133)23067962
rz-s-dns-ma.abk-stuttgart.de (193.197.154.14)23067963
rz-s-dns-sl.abk-stuttgart.de (193.197.154.16)23067962

Checks

  • !
    Serials differ
    The nameservers serve different versions of the zone: 23067962 on dns1.belwue.de (129.143.2.10), dns1.belwue.de (2001:7c0::53:10), dns3.belwue.de (129.143.253.133), dns3.belwue.de (2001:7c0:0:253::133), rz-s-dns-sl.abk-stuttgart.de (193.197.154.16); 23067963 on rz-s-dns-ma.abk-stuttgart.de (193.197.154.14). This is normal for a few minutes after a change; if it lasts, zone transfers to the secondaries are failing.
    #22
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 10m, expire 14d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver rz-s-dns-ma.abk-stuttgart.de is one of the listed nameservers.
  • ✓ Contact hostmaster@abk-stuttgart.de #25
    The SOA RNAME hostmaster.abk-stuttgart.de means hostmaster@abk-stuttgart.de.
  • ✓ Counter serial #26
    The serial 23067962 is a plain counter.

DNSSEC

warn

Signed, DS published at parent

Found

Validated by resolver
yes
Denial of existence
NSEC
Signatures valid until
27 October 2026

DS at the parent

Key tagAlgorithmDigestMatches a key
11135ECDSAP256SHA256 (13)SHA256 151D12D30B55B27A…yes

DNSKEY in the zone

Key tagRoleAlgorithm
11135KSK (257)ECDSAP256SHA256 (13)

Checks

  • ✓ Signed and validated #27
    The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
  • ✓ DS matches a key #28
    The DS record at the parent matches a key in the zone: key tag 11135 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • !
    Signatures expire soon
    The earliest signature expires at 2026-10-27 19:55 UTC (in 142h0m0s). Check that automatic re-signing works.
    #30
  • i
    NSEC
    The zone uses NSEC, so its full contents can be listed by walking the NSEC chain. That is fine unless the names are sensitive.
    #31

Records

info

14 records at the apex

Found

Read from
129.143.2.10:53
TypeValueTTL
SOArz-s-dns-ma.abk-stuttgart.de. hostmaster.abk-stuttgart.de. 23067962 3600 600 1209600 36003600
NSrz-s-dns-sl.abk-stuttgart.de.3600
NSdns3.belwue.de.3600
NSdns1.belwue.de.3600
NSrz-s-dns-ma.abk-stuttgart.de.3600
A193.197.154.103600
MX10 pmg.abk-stuttgart.de.3600
TXT"Staatliche Akademie der Bildende Kuenste, Am Weissenhof 1, 70191 Stuttgart"3600
TXT"HARICA-OcYuc5FVMvKEE5ufC78"3600
TXT"v=spf1 mx a ip4:193.197.154.69/32 ip4:193.197.154.11/32 ip4:193.197.154.12/32 ip4:193.197.154.132/32 ip4:77.237.55.139 a:mail.sop-at.com mx:sop.co.at include:spf.protection.outlook.com -all"3600
TXT"google-site-verification=71SvyQCwXkX5Lv1UzgFIwsj5mJGqRlp6EsSxu03dBu0"3600
TXT"lRjHcqxuTQQJMynFibTJN7xc1mwbOuZOzYwTMGabqGc4g5uFZvvPuJFwBMX4T9mAF+yd3pBwdFsesawALAlTQA=="3600
TXT"apple-domain-verification=b9pj8CN926uYsZbq"3600
TXT"ZOOM_verify_7ibmbcRYR4K1jaazcs5eZg"3600

Checks

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