offis.de

Checked 21 October 2026, 23:41 UTC · via 8.8.8.8
!Passed with warnings
19 passed 2 warnings 0 failed 8 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-2.dfn.de, dns-3.dfn.de, dns2.offis.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de, dns2.offis.de
NS in the zone
dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de, dns2.offis.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-2.dfn.de193.174.75.54 2001:638:d:b102::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-
dns2.offis.de134.106.57.8AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.106.57.8

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-1.dfn.de, dns-2.dfn.de, dns-3.dfn.de, dns2.offis.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: dns2.offis.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): 7 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: dns2.offis.de.
    #13

Nameservers

warn

7 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 15 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 15 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 193.174.75.54NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 2001:638:d:b102::1NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 193.174.75.58NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns-3.dfn.de 2001:638:d:b103::1NOERROR, 8 ms, authoritativenoyes / yesrefused0
dns2.offis.de 134.106.57.8NOERROR, 23 ms, authoritativenoyes / yesrefused9.11.5-P4-5.1+deb10u11-Debian

Checks

  • ✓ All respond #14
    All 7 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: dns2.offis.de: "9.11.5-P4-5.1+deb10u11-Debian". 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

info

serial 463 · primary dns1.lcl.offis.de

Found

Primary (MNAME)
dns1.lcl.offis.de
Contact (RNAME)
hostmaster.offis.de
Serial
463
Refresh / retry
14400 s / 3600 s
Expire
1814400 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)463
dns-1.dfn.de (2001:638:d:b101::1)463
dns-2.dfn.de (193.174.75.54)463
dns-2.dfn.de (2001:638:d:b102::1)463
dns-3.dfn.de (193.174.75.58)463
dns-3.dfn.de (2001:638:d:b103::1)463
dns2.offis.de (134.106.57.8)463

Checks

  • ✓ Serial 463 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 4h, retry 1h, expire 21d, negative TTL 1h.
  • i
    Hidden master (not resolvable)
    The primary nameserver dns1.lcl.offis.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 hostmaster@offis.de #25
    The SOA RNAME hostmaster.offis.de means hostmaster@offis.de.
  • ✓ Counter serial #26
    The serial 463 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

13 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAdns1.lcl.offis.de. hostmaster.offis.de. 463 14400 3600 1814400 360010800
NSdns-2.dfn.de.10800
NSdns-1.dfn.de.10800
NSdns2.offis.de.10800
NSdns-3.dfn.de.10800
A134.106.57.2510800
A134.106.57.2410800
MX10 merlin2.offis.de.10800
MX10 merlin1.offis.de.10800
MX50 merlin3.offis.de.10800
TXT"v=spf1 ip4:134.106.57.0/25 ip4:134.106.1.7 include:_spf.kdo.de ~all"10800
TXT"asv=60306300f22d739b34dd122a4b689a3d"10800
TXT"google-site-verification=62eTwovqz4lLwsrw49phbRFB7dOsU0T3ISWsQzvf1-Y"10800

Checks

  • ✓ TTLs within range #32
    TTLs: A 3h, MX 3h, NS 3h. The NS TTL at the parent is 1d and in the zone 3h; 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