fh-flensburg.de

Checked 21 October 2026, 22:20 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

info

dns-2.dfn.de, dns1.fh-flensburg.de, dns2.fh-flensburg.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-2.dfn.de, dns1.fh-flensburg.de, dns2.fh-flensburg.de
NS in the zone
dns-2.dfn.de, dns1.fh-flensburg.de, dns2.fh-flensburg.de
NameserverAddressesNetwork (AS)Glue
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-
dns1.fh-flensburg.de193.175.191.201AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.191.201
dns2.fh-flensburg.de193.175.191.202AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.191.202

Checks

  • ✓ 3 nameservers #6
    Delegated to dns-2.dfn.de, dns1.fh-flensburg.de, dns2.fh-flensburg.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: dns1.fh-flensburg.de, dns2.fh-flensburg.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 2 IPv4 /24s and 1 IPv6 /48.
  • 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): 4 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: dns1.fh-flensburg.de, dns2.fh-flensburg.de.
    #13

Nameservers

warn

4 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
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
dns1.fh-flensburg.de 193.175.191.201NOERROR, 41 ms, authoritativenoyes / yesrefused9.11.3-1ubuntu1.18-Ubuntu
dns2.fh-flensburg.de 193.175.191.202NOERROR, 16 ms, authoritativenoyes / yesrefused9.11.3-1ubuntu1.18-Ubuntu

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: dns1.fh-flensburg.de: "9.11.3-1ubuntu1.18-Ubuntu"; dns2.fh-flensburg.de: "9.11.3-1ubuntu1.18-Ubuntu". 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 2025121601 · primary dns1.fh-flensburg.de

Found

Primary (MNAME)
dns1.fh-flensburg.de
Contact (RNAME)
postmaster.fh-flensburg.de
Serial
2025121601
Refresh / retry
28800 s / 7200 s
Expire
1814400 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns-2.dfn.de (193.174.75.54)2025121601
dns-2.dfn.de (2001:638:d:b102::1)2025121601
dns1.fh-flensburg.de (193.175.191.201)2025121601
dns2.fh-flensburg.de (193.175.191.202)2025121601

Checks

  • ✓ Serial 2025121601 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 8h, retry 2h, expire 21d, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns1.fh-flensburg.de is one of the listed nameservers.
  • ✓ Contact postmaster@fh-flensburg.de #25
    The SOA RNAME postmaster.fh-flensburg.de means postmaster@fh-flensburg.de.
  • ✓ Date-based serial #26
    The serial 2025121601 follows the YYYYMMDDnn convention (2025-12-16).

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

9 records at the apex

Found

Read from
193.174.75.54:53
TypeValueTTL
SOAdns1.fh-flensburg.de. postmaster.fh-flensburg.de. 2025121601 28800 7200 1814400 8640086400
NSdns1.fh-flensburg.de.86400
NSdns2.fh-flensburg.de.86400
NSdns-2.dfn.de.86400
A193.175.191.14186400
MX10 iron1-mail.hs-flensburg.de.300
MX20 iron2-mail.hs-flensburg.de.300
TXT"MS=1291E9C3E558CE8DCF0B2E169B09862D56828E84"3600
TXT"v=spf1 mx a:fhf3.fh-flensburg.de a:mail.fh-flensburg.de a:mail.stud.fh-flensburg.de ~all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 1d, MX 5m, 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