flimmo.de

Checked 21 October 2026, 22:30 UTC · via 8.8.8.8
✗Problems found
19 passed 4 warnings 1 failed 5 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

warn

ns.z3c.net, ns3.z3c.net, ns5.z3c.net

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns.z3c.net, ns3.z3c.net, ns5.z3c.net
NS in the zone
ns.z3c.net, ns3.z3c.net, ns5.z3c.net
NameserverAddressesNetwork (AS)Glue
ns.z3c.net213.239.209.39AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
ns3.z3c.net65.21.156.38AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
ns5.z3c.net136.243.18.157AS24940 HETZNER-AS - Hetzner Online GmbH, DE-

Checks

  • ✓ 3 nameservers #6
    Delegated to ns.z3c.net, ns3.z3c.net, ns5.z3c.net.
  • ✓ 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 3 IPv4 /24s and 0 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS24940 (HETZNER-AS - Hetzner Online GmbH, DE): 3 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
  • !
    No IPv6
    None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.
    #13

Nameservers

fail

2 of 3 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns.z3c.net 213.239.209.39NOERROR, 2 ms, authoritativenoyes / yesrefused9.18.49
ns3.z3c.net 65.21.156.38no responsenono / no--
ns5.z3c.net 136.243.18.157NOERROR, 2 ms, authoritativenoyes / yesrefused9.18.49

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns3.z3c.net (65.21.156.38): read udp 46.225.38.91:54201->65.21.156.38:53: read: connection refused.
    #14
  • ✓ 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: ns.z3c.net: "9.18.49"; ns5.z3c.net: "9.18.49". 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

warn

serial 202505253 · primary ns.z3c.net

Found

Primary (MNAME)
ns.z3c.net
Contact (RNAME)
hostmaster.bsn.com
Serial
202505253
Refresh / retry
36000 s / 36000 s
Expire
20000 s
Negative TTL
18000 s

Serial per nameserver

NameserverSerial
ns.z3c.net (213.239.209.39)202505253
ns5.z3c.net (136.243.18.157)202505253

Checks

  • ✓ Serial 202505253 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    retry 10h should be shorter than refresh 10h; expire 5h33m20s is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 5h33m20s must be longer than refresh + retry. Current values: refresh 10h, retry 10h, expire 5h33m20s, negative TTL 5h.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns.z3c.net is one of the listed nameservers.
  • ✓ Contact hostmaster@bsn.com #25
    The SOA RNAME hostmaster.bsn.com means hostmaster@bsn.com.
  • ✓ Counter serial #26
    The serial 202505253 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

9 records at the apex

Found

Read from
213.239.209.39:53
TypeValueTTL
SOAns.z3c.net. hostmaster.bsn.com. 202505253 36000 36000 20000 1800090000
NSns.z3c.net.86000
NSns3.z3c.net.86000
NSns5.z3c.net.86000
A195.201.92.8686000
MX100 mail.ibu.de.86000
MX50 mail.jff.de.86000
TXT"google-site-verification=wAJ1uH_hf9t68ZhU82chwEKUgcwrRNQVCxA237rgkDM"86000
TXT"v=spf1 mx a:mail.ibu.de a:mail21.ibu.de ip4:95.216.23.87 ~all"86000

Checks

  • ✓ TTLs within range #32
    TTLs: A 23h53m20s, MX 23h53m20s, NS 23h53m20s. The NS TTL at the parent is 1d and in the zone 23h53m20s; 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