mpi-cbg.de

Checked 21 October 2026, 23:30 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

dns1.gwdg.de, dns2.gwdg.de, dns3.gwdg.de, extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns1.gwdg.de, dns2.gwdg.de, dns3.gwdg.de, extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.de
NS in the zone
dns1.gwdg.de, dns2.gwdg.de, dns3.gwdg.de, extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.de
NameserverAddressesNetwork (AS)Glue
dns1.gwdg.de134.76.33.41 2a06:93c7:e1::1AS207592 GOENET - Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH, Goettingen, DE AS207592 GOENET - Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH, Goettingen, DE134.76.33.41 2a06:93c7:e1::1
dns2.gwdg.de134.76.33.42 2a06:93c7:e2::1AS207592 GOENET - Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH, Goettingen, DE AS207592 GOENET - Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH, Goettingen, DE134.76.33.42 2a06:93c7:e2::1
dns3.gwdg.de193.175.210.140AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.210.140
extdns-srv1.mpi-cbg.de141.5.10.3AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE141.5.10.3
extdns-srv2.mpi-cbg.de141.5.10.4AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE141.5.10.4

Checks

  • ✓ 5 nameservers #6
    Delegated to dns1.gwdg.de, dns2.gwdg.de, dns3.gwdg.de, extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.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: extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.de.
  • ✓ 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 2 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS207592 (GOENET - Gesellschaft fuer wissenschaftliche Datenverarbeitung mbH, Goettingen, DE): 4 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 3 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: dns3.gwdg.de, extdns-srv1.mpi-cbg.de, extdns-srv2.mpi-cbg.de.
    #13

Nameservers

info

7 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns1.gwdg.de 134.76.33.41NOERROR, 8 ms, authoritativenoyes / yesrefused-
dns1.gwdg.de 2a06:93c7:e1::1NOERROR, 8 ms, authoritativenoyes / yesrefused-
dns2.gwdg.de 134.76.33.42NOERROR, 7 ms, authoritativenoyes / yesrefused-
dns2.gwdg.de 2a06:93c7:e2::1NOERROR, 8 ms, authoritativenoyes / yesrefused-
dns3.gwdg.de 193.175.210.140NOERROR, 13 ms, authoritativenoyes / yesrefused-
extdns-srv1.mpi-cbg.de 141.5.10.3NOERROR, 16 ms, authoritativenoyes / yesrefusedfor info, ask hostmaster[at]mpi-cbg.de
extdns-srv2.mpi-cbg.de 141.5.10.4NOERROR, 16 ms, authoritativenoyes / yesrefused-

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.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: extdns-srv1.mpi-cbg.de: "for info, ask hostmaster[at]mpi-cbg.de".
    #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 2026101504 · primary extdns-srv1.mpi-cbg.de

Found

Primary (MNAME)
extdns-srv1.mpi-cbg.de
Contact (RNAME)
unix-operator.mpi-cbg.de
Serial
2026101504
Refresh / retry
3600 s / 1200 s
Expire
604800 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns1.gwdg.de (134.76.33.41)2026101504
dns1.gwdg.de (2a06:93c7:e1::1)2026101504
dns2.gwdg.de (134.76.33.42)2026101504
dns2.gwdg.de (2a06:93c7:e2::1)2026101504
dns3.gwdg.de (193.175.210.140)2026101504
extdns-srv1.mpi-cbg.de (141.5.10.3)2026101504
extdns-srv2.mpi-cbg.de (141.5.10.4)2026101504

Checks

  • ✓ Serial 2026101504 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h, retry 20m, expire 7d, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver extdns-srv1.mpi-cbg.de is one of the listed nameservers.
  • ✓ Contact unix-operator@mpi-cbg.de #25
    The SOA RNAME unix-operator.mpi-cbg.de means unix-operator@mpi-cbg.de.
  • ✓ Date-based serial #26
    The serial 2026101504 follows the YYYYMMDDnn convention (2026-10-15).

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

14 records at the apex

Found

Read from
134.76.33.41:53
TypeValueTTL
SOAextdns-srv1.mpi-cbg.de. unix-operator.mpi-cbg.de. 2026101504 3600 1200 604800 8640086400
NSdns2.gwdg.de.86400
NSdns3.gwdg.de.86400
NSextdns-srv2.mpi-cbg.de.86400
NSdns1.gwdg.de.86400
NSextdns-srv1.mpi-cbg.de.86400
A141.5.10.686400
MX10 mailcheck-srv2.mpi-cbg.de.86400
MX10 mailcheck-srv1.mpi-cbg.de.86400
TXT"google-site-verification=kgNHUwVqnriaWbgskssqWmF8WkSUXWIQg5hk0ok42Y0"86400
TXT"anthropic-domain-verification-4rj3jk=IPS1zOH8cqTAnsicb3HVg5AQ6"86400
TXT"MS=ms72869222"86400
TXT"v=spf1 include:spf.gwdg.de ip4:141.5.10.13/32 ip4:141.5.10.40/32 ip4:141.5.10.41/32 ip4:141.5.10.42/32 ip4:141.5.10.43/32 ip4:141.5.10.44/32 ip4:141.5.10.45/32 a:mail01.umantis.com a:mail02.umantis.com a:mail03.umantis.com a mx -all"86400
TXT"apple-domain-verification=x44zai94W5nUXUmB"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