tu-freiberg.de

Checked 22 October 2026, 00:41 UTC · via 8.8.8.8
!Passed with warnings
21 passed 1 warning 0 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

info

dns-1.dfn.de, dns-3.dfn.de, edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns-3.dfn.de, edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.de
NS in the zone
dns-1.dfn.de, dns-3.dfn.de, edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.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-
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-
edns1.hrz.tu-freiberg.de139.20.202.97AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE139.20.202.97
edns2.hrz.tu-freiberg.de139.20.202.98AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE139.20.202.98

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-1.dfn.de, dns-3.dfn.de, edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.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: edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.de.
  • ✓ All names resolve #9
    Every nameserver name has an address and is not an alias.
  • i
    One address family in one network
    all IPv6 addresses are in 2001:638:d::/48, while the other address family is spread over several networks.
    #10
  • 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): 6 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: edns1.hrz.tu-freiberg.de, edns2.hrz.tu-freiberg.de.
    #13

Nameservers

info

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 193.174.75.58NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 10 ms, authoritativenoyes / yesrefused0
edns1.hrz.tu-freiberg.de 139.20.202.97NOERROR, 15 ms, authoritativenoyes / yesrefused-
edns2.hrz.tu-freiberg.de 139.20.202.98NOERROR, 16 ms, authoritativenoyes / yesrefused-

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.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: dns-1.dfn.de: "0"; 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 1257 · primary edns1.hrz.tu-freiberg.de

Found

Primary (MNAME)
edns1.hrz.tu-freiberg.de
Contact (RNAME)
hostmaster.tu-freiberg.de
Serial
1257
Refresh / retry
10800 s / 3600 s
Expire
2419200 s
Negative TTL
900 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)1257
dns-1.dfn.de (2001:638:d:b101::1)1257
dns-3.dfn.de (193.174.75.58)1257
dns-3.dfn.de (2001:638:d:b103::1)1257
edns1.hrz.tu-freiberg.de (139.20.202.97)1257
edns2.hrz.tu-freiberg.de (139.20.202.98)1257

Checks

  • ✓ Serial 1257 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 28d, negative TTL 15m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver edns1.hrz.tu-freiberg.de is one of the listed nameservers.
  • ✓ Contact hostmaster@tu-freiberg.de #25
    The SOA RNAME hostmaster.tu-freiberg.de means hostmaster@tu-freiberg.de.
  • ✓ Counter serial #26
    The serial 1257 is a plain counter.

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

15 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAedns1.hrz.tu-freiberg.de. hostmaster.tu-freiberg.de. 1257 10800 3600 2419200 90028800
NSedns1.hrz.tu-freiberg.de.28800
NSdns-1.dfn.de.28800
NSdns-3.dfn.de.28800
NSedns2.hrz.tu-freiberg.de.28800
A139.20.200.7628800
MX5 mailgateway.hrz.tu-freiberg.de.600
TXT"sophos-domain-verification=b704e365621b5c4ef05b59dc33f1f1f03edb0454facd088e003977d51a7c08d7"300
TXT"v=spf1 redirect=_spf.tu-freiberg.de"300
TXT"HARICA-Vp23xaRjaXFZ9KBlwau"300
TXT"adobe-idp-site-verification=a18761e87b6dea07c777e8e3c31f1de92eaeea79d4d96c5aff5e0c6902991380"300
TXT"MS=ms48197277"300
CAA0 issue "letsencrypt.org"28800
CAA0 issue "harica.gr"28800
CAA0 iodef "mailto:security@tu-freiberg.de"28800

Checks

  • ✓ TTLs within range #32
    TTLs: A 8h, MX 10m, 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: letsencrypt.org, harica.gr.