jacobs-university.de

Checked 21 October 2026, 23:01 UTC · via 8.8.8.8
✗Problems found
17 passed 4 warnings 1 failed 7 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.iu-bremen.de, www.jacobs-utils.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns.iu-bremen.de, www.jacobs-utils.de
NS in the zone
dns.iu-bremen.de, ns-02.briteline.de, www.jacobs-utils.de
NameserverAddressesNetwork (AS)Glue
dns.iu-bremen.de212.201.44.22AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
ns-02.briteline.de (zone only)82.198.211.1 2a03:9981:0:191::2222AS30742 BRITELINE-AS - Bremen Briteline GmbH, DE AS30742 BRITELINE-AS - Bremen Briteline GmbH, DE-
www.jacobs-utils.de81.169.212.166AS6724 STRATO - Strato GmbH, DE-

Checks

  • i
    2 nameservers
    Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: dns.iu-bremen.de, www.jacobs-utils.de.
    #6
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only in the zone: ns-02.briteline.de. dns.iu-bremen.de, ns-02.briteline.de, www.jacobs-utils.de report NS dns.iu-bremen.de ns-02.briteline.de www.jacobs-utils.de.
    #7
  • ✓ 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 1 IPv6 /48.
  • ✓ 3 autonomous systems #11
    The nameservers are spread over: AS30742 (BRITELINE-AS - Bremen Briteline GmbH, DE): 2 addresses; AS6724 (STRATO - Strato GmbH, DE): 1 address; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 1 address.
  • 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: dns.iu-bremen.de, www.jacobs-utils.de.
    #13

Nameservers

fail

4 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns.iu-bremen.de 212.201.44.22NOERROR, 15 ms, authoritativenoyes / yesrefused9.18.39-0ubuntu0.24.04.8-Ubuntu
ns-02.briteline.de 82.198.211.1NOERROR, 13 ms, authoritativenoyes / yesrefused-
ns-02.briteline.de 2a03:9981:0:191::2222NOERROR, 39 ms, authoritativenoyes / yesrefused-
www.jacobs-utils.de 81.169.212.166NOERROR, 14 ms, authoritativenoyes / yesALLOWED (520 records)9.9.6-P1

Checks

  • ✓ All respond #14
    All 4 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: dns.iu-bremen.de: "9.18.39-0ubuntu0.24.04.8-Ubuntu"; www.jacobs-utils.de: "9.9.6-P1". 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: www.jacobs-utils.de (81.169.212.166): 520 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 2026052702 · primary dns.jacobs-university.de

Found

Primary (MNAME)
dns.jacobs-university.de
Contact (RNAME)
dnsroot.jacobs-university.de
Serial
2026052702
Refresh / retry
86400 s / 7200 s
Expire
604800 s
Negative TTL
60 s

Serial per nameserver

NameserverSerial
dns.iu-bremen.de (212.201.44.22)2026052702
ns-02.briteline.de (82.198.211.1)2026052702
ns-02.briteline.de (2a03:9981:0:191::2222)2026052702
www.jacobs-utils.de (81.169.212.166)2026052702

Checks

  • ✓ Serial 2026052702 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    negative caching TTL (minimum) 1m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 1d, retry 2h, expire 7d, negative TTL 1m.
    #23
  • i
    Hidden master
    The primary nameserver dns.jacobs-university.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 dnsroot@jacobs-university.de #25
    The SOA RNAME dnsroot.jacobs-university.de means dnsroot@jacobs-university.de.
  • ✓ Date-based serial #26
    The serial 2026052702 follows the YYYYMMDDnn convention (2026-05-27).

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
212.201.44.22:53
TypeValueTTL
SOAdns.jacobs-university.de. dnsroot.jacobs-university.de. 2026052702 86400 7200 604800 6060
NSns-02.briteline.de.21600
NSwww.jacobs-utils.de.21600
NSdns.iu-bremen.de.21600
A176.9.78.1821200
MX20 jacobsuniversity-de01e.mail.protection.outlook.com.3600
TXT"v=spf1 ip4:212.201.44.18/31 ip4:212.201.44.20/31 ip4:62.55.182.68 include:askadmissionsmail.co.uk include:spf.protection.outlook.com -all"3600
TXT"F7iqKlxiZb5W07CxFjsNlJoLBbG/JC0Z7N0/5+uxYiL2HsmIloNLmqccpbW0x8vN+THTMOeHYLYyo66mZy7oYQ=="3600
TXT"MS=ms63474555"3600
TXT"d365mktkey=XDLsiqxOqbBcd5cU2Skz0PSQPy1SCSECCOp62kp76lIx"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 20m, MX 1h, NS 6h. The NS TTL at the parent is 1d and in the zone 6h; 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