fh-koeln.de

Checked 21 October 2026, 22:20 UTC · via 8.8.8.8
!Passed with warnings
23 passed 2 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

info

dns-1.dfn.de, dns1.uni-koeln.de, ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns1.uni-koeln.de, ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.de
NS in the zone
dns-1.dfn.de, dns1.uni-koeln.de, ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.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-
dns1.uni-koeln.de134.95.44.35 2a00:a200:0:56::53AS5520 UNI-KOELN - Universitaet zu Koeln, DE AS5520 UNI-KOELN - Universitaet zu Koeln, DE-
ns-gwz.nz.fh-koeln.de139.6.1.66AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE139.6.1.66
ns-iwz.nz.fh-koeln.de139.6.1.2AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE139.6.1.2

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-1.dfn.de, dns1.uni-koeln.de, ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.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: ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.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 3 IPv4 /24s and 2 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS5520 (UNI-KOELN - Universitaet zu Koeln, DE): 2 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 4 addresses.
  • 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: ns-gwz.nz.fh-koeln.de, ns-iwz.nz.fh-koeln.de.
    #13

Nameservers

warn

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 13 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 13 ms, authoritativenoyes / yesrefused0
dns1.uni-koeln.de 134.95.44.35NOERROR, 11 ms, authoritativenoyes / yesrefused-
dns1.uni-koeln.de 2a00:a200:0:56::53NOERROR, 12 ms, authoritativenoyes / yesrefused-
ns-gwz.nz.fh-koeln.de 139.6.1.66NOERROR, 14 ms, authoritativenoyes / yesrefused9.11.36-RedHat-9.11.36-16.el8_10.16
ns-iwz.nz.fh-koeln.de 139.6.1.2NOERROR, 14 ms, authoritativenoyes / yesrefused9.11.36-RedHat-9.11.36-16.el8_10.16

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: ns-gwz.nz.fh-koeln.de: "9.11.36-RedHat-9.11.36-16.el8_10.16"; ns-iwz.nz.fh-koeln.de: "9.11.36-RedHat-9.11.36-16.el8_10.16". 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 2026102103 · primary ns-iwz.nz.fh-koeln.de

Found

Primary (MNAME)
ns-iwz.nz.fh-koeln.de
Contact (RNAME)
dns.fh-koeln.de
Serial
2026102103
Refresh / retry
10800 s / 1800 s
Expire
1209600 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)2026102103
dns-1.dfn.de (2001:638:d:b101::1)2026102103
dns1.uni-koeln.de (134.95.44.35)2026102103
dns1.uni-koeln.de (2a00:a200:0:56::53)2026102103
ns-gwz.nz.fh-koeln.de (139.6.1.66)2026102103
ns-iwz.nz.fh-koeln.de (139.6.1.2)2026102103

Checks

  • ✓ Serial 2026102103 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 30m, expire 14d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns-iwz.nz.fh-koeln.de is one of the listed nameservers.
  • ✓ Contact dns@fh-koeln.de #25
    The SOA RNAME dns.fh-koeln.de means dns@fh-koeln.de.
  • ✓ Date-based serial #26
    The serial 2026102103 follows the YYYYMMDDnn convention (2026-10-21).

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

pass

16 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAns-iwz.NZ.FH-Koeln.DE. dns.FH-Koeln.DE. 2026102103 10800 1800 1209600 36003600
NSdns1.Uni-Koeln.DE.3600
NSns-iwz.NZ.FH-Koeln.DE.3600
NSns-gwz.NZ.FH-Koeln.DE.3600
NSdns-1.dfn.de.3600
A139.6.10.1993600
MX10 smtp.intranet.FH-Koeln.DE.3600
TXT"HARICA-ELCPF8ClDrWhqb02JA5"3600
TXT"google-site-verification=4DI3JqRD2Ey1wPPG6NnV0CUMWodXKspfTn5yXMbS3W0"3600
TXT"v=spf1 include:spf.dynect.net include:spf.cluster4.4hr.de include:spf.nl2go.com +ip4:139.6.1.61 +ip4:139.6.1.47 +ip4:139.6.1.48 +ip4:139.6.1.49 +ip4:139.6.1.50 ?ip4:139.6.0.0/16 ~all"3600
CAA0 iodef "mailto:dns@th-koeln.de"3600
CAA0 issue "telesec.de"3600
CAA0 issue "letsencrypt.org"3600
CAA0 issue "pki.dfn.de"3600
CAA0 issue "sectigo.com"3600
CAA0 issue "harica.gr"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.
  • ✓ CAA restricts issuance #35
    Certificates may be issued by: telesec.de, letsencrypt.org, pki.dfn.de, sectigo.com, harica.gr.