izw-berlin.de

Checked 21 October 2026, 23:00 UTC · via 8.8.8.8
!Passed with warnings
22 passed 1 warning 0 failed 6 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

a1.fv-berlin.de, a2.fv-berlin.de, deneb.dfn.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
a1.fv-berlin.de, a2.fv-berlin.de, deneb.dfn.de
NS in the zone
a1.fv-berlin.de, a2.fv-berlin.de, deneb.dfn.de
NameserverAddressesNetwork (AS)Glue
a1.fv-berlin.de62.141.163.22AS20588 FVB - Forschungsverbund Berlin e.V., DE62.141.163.22
a2.fv-berlin.de62.141.163.88AS20588 FVB - Forschungsverbund Berlin e.V., DE62.141.163.88
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-

Checks

  • ✓ 3 nameservers #6
    Delegated to a1.fv-berlin.de, a2.fv-berlin.de, deneb.dfn.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ No glue needed #8
    All nameservers are outside the zone, so no glue records are needed.
  • ✓ 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 1 IPv6 /48.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS20588 (FVB - Forschungsverbund Berlin e.V., DE): 2 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 2 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: a1.fv-berlin.de, a2.fv-berlin.de.
    #13

Nameservers

info

4 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
a1.fv-berlin.de 62.141.163.22NOERROR, 25 ms, authoritativenoyes / yesrefusedunknown
a2.fv-berlin.de 62.141.163.88NOERROR, 25 ms, authoritativenoyes / yesrefusedunknown
deneb.dfn.de 192.76.176.9NOERROR, 14 ms, authoritativenoyes / yesrefused0
deneb.dfn.de 2001:638:800:1::9NOERROR, 14 ms, authoritativenoyes / yesrefused0

Checks

  • ✓ All respond #14
    All 4 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: a1.fv-berlin.de: "unknown"; a2.fv-berlin.de: "unknown"; deneb.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 2026043001 · primary a1.fv-berlin.de

Found

Primary (MNAME)
a1.fv-berlin.de
Contact (RNAME)
hostmaster.fv-berlin.de
Serial
2026043001
Refresh / retry
86400 s / 3600 s
Expire
604800 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
a1.fv-berlin.de (62.141.163.22)2026043001
a2.fv-berlin.de (62.141.163.88)2026043001
deneb.dfn.de (192.76.176.9)2026043001
deneb.dfn.de (2001:638:800:1::9)2026043001

Checks

  • ✓ Serial 2026043001 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1d, retry 1h, expire 7d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver a1.fv-berlin.de is one of the listed nameservers.
  • ✓ Contact hostmaster@fv-berlin.de #25
    The SOA RNAME hostmaster.fv-berlin.de means hostmaster@fv-berlin.de.
  • ✓ Date-based serial #26
    The serial 2026043001 follows the YYYYMMDDnn convention (2026-04-30).

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
62.141.163.22:53
TypeValueTTL
SOAa1.fv-berlin.de. hostmaster.fv-berlin.de. 2026043001 86400 3600 604800 360086400
NSa2.fv-berlin.de.86400
NSdeneb.dfn.de.86400
NSa1.fv-berlin.de.86400
A178.16.59.5486400
MX10 c1928.mx.srv.dfn.de.900
MX10 b1928.mx.srv.dfn.de.900
MX10 a1928.mx.srv.dfn.de.900
TXT"brevo-code:e869a8a798c65873e3e26fd10b6a87e0"86400
TXT"adobe-idp-site-verification=aa0df8765dc18793715ee91ea2fc9ae1303249a4770afec2f0cc46e282790da4"86400
TXT"v=spf1 ip4:62.141.164.2 ~all"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 1d, MX 15m, NS 1d.
  • ✓ 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