hfg-offenbach.de

Checked 21 October 2026, 22:50 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, dns-e-s-1.hfg-offenbach.de, dns-e-s-2.hfg-offenbach.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, dns-e-s-1.hfg-offenbach.de, dns-e-s-2.hfg-offenbach.de
NS in the zone
dns-1.dfn.de, dns-3.dfn.de, dns-e-s-1.hfg-offenbach.de, dns-e-s-2.hfg-offenbach.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-
dns-e-s-1.hfg-offenbach.de195.37.12.3 2001:638:312:3::2AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE195.37.12.3 2001:638:312:3::2
dns-e-s-2.hfg-offenbach.de195.37.12.4 2001:638:312:3::3AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE195.37.12.4 2001:638:312:3::3

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-1.dfn.de, dns-3.dfn.de, dns-e-s-1.hfg-offenbach.de, dns-e-s-2.hfg-offenbach.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: dns-e-s-1.hfg-offenbach.de, dns-e-s-2.hfg-offenbach.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 2 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): 8 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

8 of 8 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, 15 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 193.174.75.58NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 11 ms, authoritativenoyes / yesrefused0
dns-e-s-1.hfg-offenbach.de 195.37.12.3NOERROR, 5 ms, authoritativenoyes / yesrefused-
dns-e-s-1.hfg-offenbach.de 2001:638:312:3::2NOERROR, 4 ms, authoritativenoyes / yesrefused-
dns-e-s-2.hfg-offenbach.de 195.37.12.4NOERROR, 4 ms, authoritativenoyes / yesrefused-
dns-e-s-2.hfg-offenbach.de 2001:638:312:3::3NOERROR, 4 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 8 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

info

serial 933 · primary dns-e-m-1.hfg-offenbach.de

Found

Primary (MNAME)
dns-e-m-1.hfg-offenbach.de
Contact (RNAME)
administrator.hfg-offenbach.de
Serial
933
Refresh / retry
3600 s / 900 s
Expire
604800 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)933
dns-1.dfn.de (2001:638:d:b101::1)933
dns-3.dfn.de (193.174.75.58)933
dns-3.dfn.de (2001:638:d:b103::1)933
dns-e-s-1.hfg-offenbach.de (195.37.12.3)933
dns-e-s-1.hfg-offenbach.de (2001:638:312:3::2)933
dns-e-s-2.hfg-offenbach.de (195.37.12.4)933
dns-e-s-2.hfg-offenbach.de (2001:638:312:3::3)933

Checks

  • ✓ Serial 933 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 15m, expire 7d, negative TTL 1h.
  • i
    Hidden master (not resolvable)
    The primary nameserver dns-e-m-1.hfg-offenbach.de is not listed as a nameserver and does not resolve publicly: a hidden master, or a placeholder name. Some tools (e.g. dynamic updates) use MNAME to find the primary.
    #24
  • ✓ Contact administrator@hfg-offenbach.de #25
    The SOA RNAME administrator.hfg-offenbach.de means administrator@hfg-offenbach.de.
  • ✓ Counter serial #26
    The serial 933 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

info

11 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOADNS-e-m-1.hfg-offenbach.de. administrator.hfg-offenbach.de. 933 3600 900 604800 36001209600
NSDNS-e-s-1.hfg-offenbach.de.3600
NSDNS-e-s-2.hfg-offenbach.de.3600
NSdns-1.dfn.de.3600
NSdns-3.dfn.de.3600
A49.12.115.223600
MX10 mail03.hfg-offenbach.de.3600
TXT"HARICA-WWXK5RUjaXUHy2pvCj4"3600
TXT"adobe-idp-site-verification=0dcda1f1b4efbc459c8c27ea49783ed2be62844443ca9e14219339707fc032d8"3600
TXT"v=spf1 mx -all"3600
TXT"google-site-verification=BqZHFUdrHdSRnaHOPL49jDbEP3fPfnNIpQKACG39EXI"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.
  • 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