schluetersche.de

Checked 22 October 2026, 00:01 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

ns.heise.de, robotns2.second-ns.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns.heise.de, robotns2.second-ns.de
NS in the zone
ns.heise.de, robotns2.second-ns.de
NameserverAddressesNetwork (AS)Glue
ns.heise.de193.99.145.37 2a00:e68:14:800::d1ceAS15743 NETDE - net.de AG, DE AS15743 NETDE - net.de AG, DE193.99.145.37 2a00:e68:14:800::d1ce
robotns2.second-ns.de213.133.100.103 2a01:4f8:0:1::5ddc:2AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-

Checks

  • i
    2 nameservers
    Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: ns.heise.de, robotns2.second-ns.de.
    #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.
  • ✓ Nameservers in different networks #10
    The nameservers are spread over 2 IPv4 /24s and 2 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS15743 (NETDE - net.de AG, DE): 2 addresses; AS24940 (HETZNER-AS - Hetzner Online GmbH, 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
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

pass

4 of 4 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns.heise.de 193.99.145.37NOERROR, 12 ms, authoritativenoyes / yesrefused-
ns.heise.de 2a00:e68:14:800::d1ceNOERROR, 15 ms, authoritativenoyes / yesrefused-
robotns2.second-ns.de 213.133.100.103NOERROR, 0 ms, authoritativenoyes / yesrefused-
robotns2.second-ns.de 2a01:4f8:0:1::5ddc:2NOERROR, 0 ms, authoritativenoyes / yesrefused-

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.
  • ✓ No version disclosed #17
    The nameservers don't reveal their software version.
  • ✓ 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 2026101048 · primary index01.heise.de

Found

Primary (MNAME)
index01.heise.de
Contact (RNAME)
hostmaster.heise.de
Serial
2026101048
Refresh / retry
14400 s / 3600 s
Expire
604800 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
ns.heise.de (193.99.145.37)2026101048
ns.heise.de (2a00:e68:14:800::d1ce)2026101048
robotns2.second-ns.de (213.133.100.103)2026101048
robotns2.second-ns.de (2a01:4f8:0:1::5ddc:2)2026101048

Checks

  • ✓ Serial 2026101048 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 4h, retry 1h, expire 7d, negative TTL 1d.
  • i
    Hidden master (not resolvable)
    The primary nameserver index01.heise.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@heise.de #25
    The SOA RNAME hostmaster.heise.de means hostmaster@heise.de.
  • ✓ Date-based serial #26
    The serial 2026101048 follows the YYYYMMDDnn convention (2026-10-10).

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

13 records at the apex

Found

Read from
193.99.145.37:53
TypeValueTTL
SOAindex01.heise.de. hostmaster.heise.de. 2026101048 14400 3600 604800 8640086400
NSns.heise.de.86400
NSrobotns2.second-ns.de.86400
A3.123.247.10986400
MX10 mx16a.antispameurope.com.86400
MX10 mx16d.antispameurope.com.86400
MX10 mx16b.antispameurope.com.86400
MX10 mx16c.antispameurope.com.86400
TXT"windsurf-verification=w7eLMkPxEK1GO7KEO34Xr3KHVJVor_QcTjZrGzfG-6M="86400
TXT"google-site-verification=IafrUewBLK4g8WhcEe8kICDanpbk92yXpaV2zOi3ucE"86400
TXT"anthropic-domain-verification-y41asj=d2zPtBy6Ve2pcNf2lT56NHScP"86400
TXT"v=spf1 include:spf-part1.schluetersche.de include:spf-part2.schluetersche.de include:spf-part3.schluetersche.de include:spf-part4.schluetersche.de include:spf-part5.schluetersche.de -all"86400
TXT"facebook-domain-verification=mnfg6p68ozklitgdsdfg0suqxxq6l5"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 1d, MX 1d, 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