khm.de

Checked 21 October 2026, 23:02 UTC · via 8.8.8.8
✗Problems found
20 passed 3 warnings 2 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

deneb.dfn.de, noc2.rrz.uni-koeln.de, riesling.khm.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
deneb.dfn.de, noc2.rrz.uni-koeln.de, riesling.khm.de
NS in the zone
deneb.dfn.de, dns1.uni-koeln.de, riesling.khm.de
NameserverAddressesNetwork (AS)Glue
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-
dns1.uni-koeln.de (zone only)134.95.44.35 2a00:a200:0:56::53AS5520 UNI-KOELN - Universitaet zu Koeln, DE AS5520 UNI-KOELN - Universitaet zu Koeln, DE-
noc2.rrz.uni-koeln.de (parent only)134.95.129.23 2a00:a200:0:50::53AS5520 UNI-KOELN - Universitaet zu Koeln, DE AS5520 UNI-KOELN - Universitaet zu Koeln, DE134.95.129.23 2a00:a200:0:50::53
riesling.khm.de194.95.160.47AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE194.95.160.47

Checks

  • ✓ 3 nameservers #6
    Delegated to deneb.dfn.de, noc2.rrz.uni-koeln.de, riesling.khm.de.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only at the parent: noc2.rrz.uni-koeln.de; only in the zone: dns1.uni-koeln.de. deneb.dfn.de, dns1.uni-koeln.de, riesling.khm.de report NS deneb.dfn.de dns1.uni-koeln.de riesling.khm.de.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: riesling.khm.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 4 IPv4 /24s and 2 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS5520 (UNI-KOELN - Universitaet zu Koeln, DE): 4 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 3 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: riesling.khm.de.
    #13

Nameservers

fail

5 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
deneb.dfn.de 192.76.176.9NOERROR, 14 ms, authoritativenoyes / yesrefused0
deneb.dfn.de 2001:638:800:1::9NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns1.uni-koeln.de 134.95.44.35NOERROR, 11 ms, authoritativenoyes / yesrefused-
dns1.uni-koeln.de 2a00:a200:0:56::53NOERROR, 11 ms, authoritativenoyes / yesrefused-
noc2.rrz.uni-koeln.de 134.95.129.23REFUSED, 11 ms, NOT authoritativenono / yesrefusedNone of your business
noc2.rrz.uni-koeln.de 2a00:a200:0:50::53REFUSED, 12 ms, NOT authoritativenono / yesrefusedNone of your business
riesling.khm.de 194.95.160.47NOERROR, 7 ms, authoritativenoyes / yesrefused9.20.24

Checks

  • ✓ All respond #14
    All 7 nameserver addresses answered.
  • ✗
    Lame delegation
    These nameservers don't answer authoritatively for the zone, so resolvers ignore them: noc2.rrz.uni-koeln.de (134.95.129.23): REFUSED, authoritative=false; noc2.rrz.uni-koeln.de (2a00:a200:0:50::53): REFUSED, authoritative=false.
    #15
  • ✓ 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: riesling.khm.de: "9.20.24". Hide or replace the version string.
    #17
  • ✓ Zone transfers refused #18
    No nameserver allows a zone transfer to the public.
  • ✗
    No DNS over TCP
    DNS over TCP is required (RFC 7766); without it, large answers such as DNSSEC responses fail. Not answering over TCP: noc2.rrz.uni-koeln.de (134.95.129.23): ; noc2.rrz.uni-koeln.de (2a00:a200:0:50::53): .
    #19
  • ✓ EDNS supported #20
    All nameservers support EDNS(0).
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

pass

serial 2026090901 · primary riesling.khm.de

Found

Primary (MNAME)
riesling.khm.de
Contact (RNAME)
hostmaster.mail.khm.de
Serial
2026090901
Refresh / retry
28800 s / 7200 s
Expire
1814400 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
deneb.dfn.de (192.76.176.9)2026090901
deneb.dfn.de (2001:638:800:1::9)2026090901
dns1.uni-koeln.de (134.95.44.35)2026090901
dns1.uni-koeln.de (2a00:a200:0:56::53)2026090901
riesling.khm.de (194.95.160.47)2026090901

Checks

  • ✓ Serial 2026090901 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 riesling.khm.de is one of the listed nameservers.
  • ✓ Contact hostmaster@mail.khm.de #25
    The SOA RNAME hostmaster.mail.khm.de means hostmaster@mail.khm.de.
  • ✓ Date-based serial #26
    The serial 2026090901 follows the YYYYMMDDnn convention (2026-09-09).

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

18 records at the apex

Found

Read from
192.76.176.9:53
TypeValueTTL
SOAriesling.khm.de. hostmaster.mail.khm.de. 2026090901 28800 7200 1814400 864003600
NSdns1.Uni-Koeln.DE.28800
NSriesling.khm.de.28800
NSdeneb.dfn.DE.28800
A194.95.160.3228800
MX100 mail2.khm.de.28800
MX10 mail.khm.de.28800
MX100 mail1.khm.de.28800
MX100 mail3.khm.de.28800
TXT"HARICA-OizrXEnyzEB5JKPCKd6"28800
TXT"adobe-idp-site-verification=91e2bb288d7e28b2a82ffb765c5d845ace2d3b7dd4ced84235b4cba539545e9b"28800
TXT"ZOOM_verify_jtVWb-EERiKRAr3Gr-UUUg"28800
TXT"apple-domain-verification=rmGLc9LqCmh4o2Gw"28800
TXT"MS=4EFC386CCF4EB5ED40A2C8FA0F5C52293D380DE2"28800
TXT"v=spf1 mx ip4:37.49.159.121/32 ip4:37.123.109.243/32 " "include:nl.khm.de a:uhura2.skim.hs-owl.de include:spf-eu.exlibrisgroup.com a:khm.rockt.org " "a:jobs.khm.de include:_spf.b-ite.com a:icms-nrw.de a:tho-prx-prod01-app-node-01.tho.icms-nrw.de -all"28800
TXT"spycloud-domain-verification=89c25cf6-e29c-4d61-89b1-3687c0ec9e66"28800
CAA0 issue "sectigo.com"28800
CAA0 issue "harica.gr"28800

Checks

  • ✓ TTLs within range #32
    TTLs: A 8h, MX 8h, NS 8h. The NS TTL at the parent is 1d and in the zone 8h; 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: sectigo.com, harica.gr.