slub-dresden.de

Checked 22 October 2026, 00:22 UTC · via 8.8.8.8
!Passed with warnings
22 passed 3 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

warn

albert.slub-dresden.de, deneb.dfn.de, robotns2.second-ns.de, robotns3.second-ns.com, sdvdns2.slub-dresden.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
albert.slub-dresden.de, deneb.dfn.de, robotns2.second-ns.de, robotns3.second-ns.com, sdvdns2.slub-dresden.de
NS in the zone
albert.slub-dresden.de, deneb.dfn.de, ns1.first-ns.de, robotns2.second-ns.de, robotns3.second-ns.com, sdvdns2.slub-dresden.de
NameserverAddressesNetwork (AS)Glue
albert.slub-dresden.de194.95.142.2AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE194.95.142.2
deneb.dfn.de192.76.176.9 2001:638:800:1::9AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
ns1.first-ns.de (zone only)213.239.242.238 2a01:4f8:0:a101::a:1AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
robotns2.second-ns.de213.133.100.103 2a01:4f8:0:1::5ddc:2AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
robotns3.second-ns.com193.47.99.3 2001:67c:192c::add:a3AS12337 NORIS-NETWORK - noris network AG, DE AS12337 NORIS-NETWORK - noris network AG, DE-
sdvdns2.slub-dresden.de194.95.142.29AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE194.95.142.29

Checks

  • ✓ 5 nameservers #6
    Delegated to albert.slub-dresden.de, deneb.dfn.de, robotns2.second-ns.de, robotns3.second-ns.com, sdvdns2.slub-dresden.de.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only in the zone: ns1.first-ns.de. albert.slub-dresden.de, deneb.dfn.de, ns1.first-ns.de, robotns2.second-ns.de, robotns3.second-ns.com, sdvdns2.slub-dresden.de report NS albert.slub-dresden.de deneb.dfn.de ns1.first-ns.de robotns2.second-ns.de robotns3.second-ns.com sdvdns2.slub-dresden.de.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: albert.slub-dresden.de, sdvdns2.slub-dresden.de.
  • ✓ 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 5 IPv4 /24s and 3 IPv6 /48s.
  • ✓ 3 autonomous systems #11
    The nameservers are spread over: AS12337 (NORIS-NETWORK - noris network AG, DE): 2 addresses; AS24940 (HETZNER-AS - Hetzner Online GmbH, DE): 4 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 4 addresses.
  • ✓ Nameserver names under 2 TLDs #12
    Nameserver names use the TLDs .com, .de.
  • i
    Partly IPv6
    These nameservers have no IPv6 address: albert.slub-dresden.de, sdvdns2.slub-dresden.de.
    #13

Nameservers

warn

10 of 10 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
albert.slub-dresden.de 194.95.142.2NOERROR, 15 ms, authoritativenoyes / yesrefused9.20.29-1~deb13u1-Debian
deneb.dfn.de 192.76.176.9NOERROR, 14 ms, authoritativenoyes / yesrefused0
deneb.dfn.de 2001:638:800:1::9NOERROR, 14 ms, authoritativenoyes / yesrefused0
ns1.first-ns.de 213.239.242.238NOERROR, 5 ms, authoritativenoyes / yesrefused-
ns1.first-ns.de 2a01:4f8:0:a101::a:1NOERROR, 5 ms, authoritativenoyes / yesrefused-
robotns2.second-ns.de 213.133.100.103NOERROR, 2 ms, authoritativenoyes / yesrefused-
robotns2.second-ns.de 2a01:4f8:0:1::5ddc:2NOERROR, 1 ms, authoritativenoyes / yesrefused-
robotns3.second-ns.com 193.47.99.3NOERROR, 8 ms, authoritativenoyes / yesrefused-
robotns3.second-ns.com 2001:67c:192c::add:a3NOERROR, 7 ms, authoritativenoyes / yesrefused-
sdvdns2.slub-dresden.de 194.95.142.29NOERROR, 16 ms, authoritativenoyes / yesrefused9.20.29-1~deb13u1-Debian

Checks

  • ✓ All respond #14
    All 10 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: albert.slub-dresden.de: "9.20.29-1~deb13u1-Debian"; sdvdns2.slub-dresden.de: "9.20.29-1~deb13u1-Debian". 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 2026101501 · primary albert.slub-dresden.de

Found

Primary (MNAME)
albert.slub-dresden.de
Contact (RNAME)
hostmaster.slub-dresden.de
Serial
2026101501
Refresh / retry
3600 s / 1800 s
Expire
1209600 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
albert.slub-dresden.de (194.95.142.2)2026101501
deneb.dfn.de (192.76.176.9)2026101501
deneb.dfn.de (2001:638:800:1::9)2026101501
ns1.first-ns.de (213.239.242.238)2026101501
ns1.first-ns.de (2a01:4f8:0:a101::a:1)2026101501
robotns2.second-ns.de (213.133.100.103)2026101501
robotns2.second-ns.de (2a01:4f8:0:1::5ddc:2)2026101501
robotns3.second-ns.com (193.47.99.3)2026101501
robotns3.second-ns.com (2001:67c:192c::add:a3)2026101501
sdvdns2.slub-dresden.de (194.95.142.29)2026101501

Checks

  • ✓ Serial 2026101501 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 30m, expire 14d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver albert.slub-dresden.de is one of the listed nameservers.
  • ✓ Contact hostmaster@slub-dresden.de #25
    The SOA RNAME hostmaster.slub-dresden.de means hostmaster@slub-dresden.de.
  • ✓ Date-based serial #26
    The serial 2026101501 follows the YYYYMMDDnn convention (2026-10-15).

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

10 records at the apex

Found

Read from
194.95.142.2:53
TypeValueTTL
SOAalbert.slub-dresden.de. hostmaster.slub-dresden.de. 2026101501 3600 1800 1209600 36003600
NSrobotns2.second-ns.de.3600
NSdeneb.dfn.de.3600
NSalbert.slub-dresden.de.3600
NSns1.first-ns.de.3600
NSsdvdns2.slub-dresden.de.3600
NSrobotns3.second-ns.com.3600
A194.95.142.453600
MX5 mailgate.slub-dresden.de.3600
TXT"v=spf1 ip4:194.95.142.113 ip4:194.95.142.114 ip4:194.95.142.115 -all"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