zois-berlin.de

Checked 22 October 2026, 01:20 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

warn

dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de
NS in the zone
dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de
NameserverAddressesNetwork (AS)Glue
dns-1.dfn.de193.174.75.50 2001:638:d:b101::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
dns-2.dfn.de193.174.75.54 2001:638:d:b102::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
dns-3.dfn.de193.174.75.58 2001:638:d:b103::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-

Checks

  • ✓ 3 nameservers #6
    Delegated to dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.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 one network
    all IPv4 addresses are in 193.174.75.0/24; all IPv6 addresses are in 2001:638:d::/48. A single network failure takes all nameservers down; RFC 2182 recommends topologically separate networks (anycast setups are an exception).
    #10
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., 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
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

info

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 12 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 193.174.75.54NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 2001:638:d:b102::1NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 193.174.75.58NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 10 ms, authoritativenoyes / yesrefused0

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.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: dns-1.dfn.de: "0"; dns-2.dfn.de: "0"; dns-3.dfn.de: "0".
    #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 2025101445 · primary dns-1.dfn.de

Found

Primary (MNAME)
dns-1.dfn.de
Contact (RNAME)
hostmaster.zois-berlin.de
Serial
2025101445
Refresh / retry
28800 s / 7200 s
Expire
864000 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)2025101445
dns-1.dfn.de (2001:638:d:b101::1)2025101445
dns-2.dfn.de (193.174.75.54)2025101445
dns-2.dfn.de (2001:638:d:b102::1)2025101445
dns-3.dfn.de (193.174.75.58)2025101445
dns-3.dfn.de (2001:638:d:b103::1)2025101445

Checks

  • ✓ Serial 2025101445 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 8h, retry 2h, expire 10d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns-1.dfn.de is one of the listed nameservers.
  • ✓ Contact hostmaster@zois-berlin.de #25
    The SOA RNAME hostmaster.zois-berlin.de means hostmaster@zois-berlin.de.
  • ✓ Date-based serial #26
    The serial 2025101445 follows the YYYYMMDDnn convention (2025-10-14).

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

19 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAdns-1.dfn.de. hostmaster.zois-berlin.de. 2025101445 28800 7200 864000 36001209600
NSdns-2.dfn.de.3600
NSdns-1.dfn.de.3600
NSdns-3.dfn.de.3600
A5.45.108.1123600
AAAA2a03:4000:6:f03f::13600
MX10 b2581.mx.srv.dfn.de.3600
MX10 c2581.mx.srv.dfn.de.3600
MX10 a2581.mx.srv.dfn.de.3600
TXT"apple-domain-verification=svr0nQkwSGJFV4JS"3600
TXT"v=spf1 a mx a:outlook.zois-berlin.de ip4:188.1.245.54 include:spf.protection.outlook.com -all"3600
TXT"MS=ms17454891"3600
TXT"atlassian-domain-verification=FeoQEWuEMQr9bGatOjRqYT3j0ubfEuWnss/88ne4J/buENc043LEtkFXmxXoGJR1"3600
TXT"atlassian-sending-domain-verification=5d0a8ae5-44e1-4266-802e-1c2da93f742c"3600
TXT"MS=ms17531715"3600
TXT"cisco-ci-domain-verification=300028dec72d1e2e0602a3d5a75a88c0da1d55ea279a979ddec5b52ef9e1de8e"3600
TXT"MS=93936500CA558BEE253E98B41C257E030FB77476"3600
TXT"HARICA-TOnurIDCx90jOsHhzI0"3600
TXT"adobe-idp-site-verification=1ee6044e51c612413a94f345369d9d1681ed8a60915d51a977f849e61203a74b"3600

Checks

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