maintower.de

Checked 21 October 2026, 23:21 UTC · via 8.8.8.8
!Passed with warnings
20 passed 2 warnings 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

ns1.izb.net, ns2.izb.net

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns1.izb.net, ns2.izb.net
NS in the zone
ns1.izb.net, ns2.izb.net
NameserverAddressesNetwork (AS)Glue
ns1.izb.net212.34.64.13 2a02:c00::d422:400dAS12316 FITSNET - Finanz Informatik Technologie Service GmbH & Co. KG, DE AS12316 FITSNET - Finanz Informatik Technologie Service GmbH & Co. KG, DE-
ns2.izb.net212.34.65.13 2a02:c00::d422:410dAS12316 FITSNET - Finanz Informatik Technologie Service GmbH & Co. KG, DE AS12316 FITSNET - Finanz Informatik Technologie Service GmbH & Co. KG, DE-

Checks

  • i
    2 nameservers
    Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: ns1.izb.net, ns2.izb.net.
    #6
  • ✓ 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.
  • i
    One address family in one network
    all IPv6 addresses are in 2a02:c00::/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 (AS12316 (FITSNET - Finanz Informatik Technologie Service GmbH & Co. KG, DE): 4 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 .net
    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

warn

4 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.izb.net 212.34.64.13NOERROR, 26 ms, authoritativenoyes / yesrefused9.18.41
ns1.izb.net 2a02:c00::d422:400dNOERROR, 25 ms, authoritativenoyes / yesrefused9.18.41
ns2.izb.net 212.34.65.13NOERROR, 26 ms, authoritativenoyes / yesrefused9.18.41
ns2.izb.net 2a02:c00::d422:410dNOERROR, 25 ms, authoritativenoyes / yesrefused9.18.41

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.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns1.izb.net: "9.18.41"; ns2.izb.net: "9.18.41". 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

pass

serial 2026081000 · primary ns1.izb.net

Found

Primary (MNAME)
ns1.izb.net
Contact (RNAME)
hostmaster.domainmaster.f-i-ts.de
Serial
2026081000
Refresh / retry
3600 s / 1200 s
Expire
3600000 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
ns1.izb.net (212.34.64.13)2026081000
ns1.izb.net (2a02:c00::d422:400d)2026081000
ns2.izb.net (212.34.65.13)2026081000
ns2.izb.net (2a02:c00::d422:410d)2026081000

Checks

  • ✓ Serial 2026081000 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 20m, expire 1000h, negative TTL 10m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.izb.net is one of the listed nameservers.
  • ✓ Contact hostmaster@domainmaster.f-i-ts.de #25
    The SOA RNAME hostmaster.domainmaster.f-i-ts.de means hostmaster@domainmaster.f-i-ts.de.
  • ✓ Date-based serial #26
    The serial 2026081000 follows the YYYYMMDDnn convention (2026-08-10).

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

5 records at the apex

Found

Read from
212.34.64.13:53
TypeValueTTL
SOAns1.izb.net. hostmaster.domainmaster.f-i-ts.de. 2026081000 3600 1200 3600000 6003600
NSns2.izb.net.3600
NSns1.izb.net.3600
A192.124.249.113300
MX10 pmx1.maintower.de.43200

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, MX 12h, 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