tu-chemnitz.de

Checked 22 October 2026, 00:41 UTC · via 8.8.8.8
iAll checks passed
28 passed 0 warnings 0 failed 5 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

ceres.hrz.tu-chemnitz.de, dns-3.dfn.de, eris.hrz.tu-chemnitz.de, secondary.rrze.uni-erlangen.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ceres.hrz.tu-chemnitz.de, dns-3.dfn.de, eris.hrz.tu-chemnitz.de, secondary.rrze.uni-erlangen.de
NS in the zone
ceres.hrz.tu-chemnitz.de, dns-3.dfn.de, eris.hrz.tu-chemnitz.de, secondary.rrze.uni-erlangen.de
NameserverAddressesNetwork (AS)Glue
ceres.hrz.tu-chemnitz.de134.109.6.1 2001:638:911:301:134:109:6:1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.109.6.1 2001:638:911:301:134:109:6:1
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-
eris.hrz.tu-chemnitz.de134.109.133.17 2001:638:911:b01:134:109:133:17AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.109.133.17 2001:638:911:b01:134:109:133:17
secondary.rrze.uni-erlangen.de131.188.3.4 131.188.0.52 2001:638:a000:1055:53::3 2001:638:a000:1001:53::3AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-

Checks

  • ✓ 4 nameservers #6
    Delegated to ceres.hrz.tu-chemnitz.de, dns-3.dfn.de, eris.hrz.tu-chemnitz.de, secondary.rrze.uni-erlangen.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: ceres.hrz.tu-chemnitz.de, eris.hrz.tu-chemnitz.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 5 IPv4 /24s and 3 IPv6 /48s.
  • 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): 10 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

10 of 10 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ceres.hrz.tu-chemnitz.de 134.109.6.1NOERROR, 17 ms, authoritativenoyes / yesrefused-
ceres.hrz.tu-chemnitz.de 2001:638:911:301:134:109:6:1NOERROR, 15 ms, authoritativenoyes / yesrefused-
dns-3.dfn.de 193.174.75.58NOERROR, 10 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 8 ms, authoritativenoyes / yesrefused0
eris.hrz.tu-chemnitz.de 134.109.133.17NOERROR, 17 ms, authoritativenoyes / yesrefused-
eris.hrz.tu-chemnitz.de 2001:638:911:b01:134:109:133:17NOERROR, 15 ms, authoritativenoyes / yesrefused-
secondary.rrze.uni-erlangen.de 131.188.3.4NOERROR, 7 ms, authoritativenoyes / yesrefused-
secondary.rrze.uni-erlangen.de 131.188.0.52NOERROR, 7 ms, authoritativenoyes / yesrefused-
secondary.rrze.uni-erlangen.de 2001:638:a000:1055:53::3NOERROR, 7 ms, authoritativenoyes / yesrefused-
secondary.rrze.uni-erlangen.de 2001:638:a000:1001:53::3NOERROR, 7 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 10 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-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 2021808614 · primary ceres.hrz.tu-chemnitz.de

Found

Primary (MNAME)
ceres.hrz.tu-chemnitz.de
Contact (RNAME)
hostmaster.tu-chemnitz.de
Serial
2021808614
Refresh / retry
10800 s / 3600 s
Expire
2419200 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
ceres.hrz.tu-chemnitz.de (134.109.6.1)2021808614
ceres.hrz.tu-chemnitz.de (2001:638:911:301:134:109:6:1)2021808614
dns-3.dfn.de (193.174.75.58)2021808614
dns-3.dfn.de (2001:638:d:b103::1)2021808614
eris.hrz.tu-chemnitz.de (134.109.133.17)2021808614
eris.hrz.tu-chemnitz.de (2001:638:911:b01:134:109:133:17)2021808614
secondary.rrze.uni-erlangen.de (131.188.3.4)2021808614
secondary.rrze.uni-erlangen.de (131.188.0.52)2021808614
secondary.rrze.uni-erlangen.de (2001:638:a000:1055:53::3)2021808614
secondary.rrze.uni-erlangen.de (2001:638:a000:1001:53::3)2021808614

Checks

  • ✓ Serial 2021808614 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 28d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ceres.hrz.tu-chemnitz.de is one of the listed nameservers.
  • ✓ Contact hostmaster@tu-chemnitz.de #25
    The SOA RNAME hostmaster.tu-chemnitz.de means hostmaster@tu-chemnitz.de.
  • ✓ Timestamp serial #26
    The serial 2021808614 is a Unix timestamp (2034-01-25 13:30 UTC).

DNSSEC

pass

Signed, DS published at parent

Found

Validated by resolver
yes
Denial of existence
NSEC3
NSEC3
0 iterations, 0-byte salt
Signatures valid until
29 October 2026

DS at the parent

Key tagAlgorithmDigestMatches a key
1039RSASHA256 (8)SHA256 E744BA263B897D1C…yes

DNSKEY in the zone

Key tagRoleAlgorithm
1039KSK (257)RSASHA256 (8)
40654ZSK (256)RSASHA256 (8)

Checks

  • ✓ Signed and validated #27
    The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
  • ✓ DS matches a key #28
    The DS record at the parent matches a key in the zone: key tag 1039 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: RSASHA256 (8).
  • ✓ Signatures valid until 2026-10-29 #30
    The earliest DNSKEY/SOA signature expires at 2026-10-29 03:45 UTC.
  • ✓ NSEC3 as recommended #31
    The zone uses NSEC3 with 0 iterations and no salt (RFC 9276).

Records

pass

18 records at the apex

Found

Read from
134.109.6.1:53
TypeValueTTL
SOAceres.hrz.tu-chemnitz.de. hostmaster.tu-chemnitz.de. 2021808614 10800 3600 2419200 360086400
NSeris.hrz.tu-chemnitz.de.300
NSceres.hrz.tu-chemnitz.de.300
NSdns-3.dfn.de.300
NSsecondary.rrze.uni-erlangen.de.300
A134.109.133.7300
AAAA2001:638:911:b01:134:109:133:7300
MX1 kyle.hrz.tu-chemnitz.de.300
MX1 ezra.hrz.tu-chemnitz.de.300
TXT"google-site-verification=5XIMxbUxIRiPJF7IuWJWFq3TVhk-h8nQZ8aW_OqkPO8"600
TXT"v=spf1 ip4:134.109.229.63 ip4:134.109.229.193 ip6:2001:638:911:b0e:134:109:229:63 ip6:2001:638:911:b0e:134:109:229:193 include:_spf.o155.mx.srv.dfn.de ~all"600
CAA0 issuewild "harica.gr"600
CAA0 issuewild "pki.dfn.de"600
CAA0 iodef "mailto:ca@hrz.tu-chemnitz.de"600
CAA0 issue "letsencrypt.org"600
CAA0 issue "harica.gr"600
CAA0 issue "pki.dfn.de"600
CAA0 issuewild "letsencrypt.org"600

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, AAAA 5m, MX 5m, NS 5m. The NS TTL at the parent is 1d and in the zone 5m; 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: harica.gr, pki.dfn.de, letsencrypt.org.