leibniz-lib.de

Checked 21 October 2026, 23:11 UTC · via 8.8.8.8
!Passed with warnings
21 passed 2 warnings 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

warn

dns1.uni-bonn.de, dns2.uni-bonn.de, dns3.uni-bonn.de, unibn-dns.uni-koeln.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns1.uni-bonn.de, dns2.uni-bonn.de, dns3.uni-bonn.de, unibn-dns.uni-koeln.de
NS in the zone
dns1.uni-bonn.de, dns2.uni-bonn.de, dns3.uni-bonn.de, unibn-dns.uni-koeln.de
NameserverAddressesNetwork (AS)Glue
dns1.uni-bonn.de131.220.16.220 2a00:5ba0:0:1010::83dc:10dcAS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE131.220.16.220 2a00:5ba0:0:1010::83dc:10dc
dns2.uni-bonn.de131.220.18.138 2a00:5ba0:0:1001::83dc:128aAS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE131.220.18.138 2a00:5ba0:0:1001::83dc:128a
dns3.uni-bonn.de131.220.14.203 2a00:5ba0:0:1002::83dc:ecbAS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE131.220.14.203
unibn-dns.uni-koeln.de134.95.48.166AS5520 UNI-KOELN - Universitaet zu Koeln, DE-

Checks

  • ✓ 4 nameservers #6
    Delegated to dns1.uni-bonn.de, dns2.uni-bonn.de, dns3.uni-bonn.de, unibn-dns.uni-koeln.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • !
    Glue differs from the zone
    The addresses at the parent (glue) differ from the addresses in the zone: dns3.uni-bonn.de (glue 131.220.14.203, zone 131.220.14.203, 2a00:5ba0:0:1002::83dc:ecb). Update the glue at your registrar.
    #8
  • ✓ 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 2a00:5ba0::/48, while the other address family is spread over several networks.
    #10
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS5520 (UNI-KOELN - Universitaet zu Koeln, DE): 1 address; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 6 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: unibn-dns.uni-koeln.de.
    #13

Nameservers

pass

7 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns1.uni-bonn.de 131.220.16.220NOERROR, 8 ms, authoritativenoyes / yesrefused-
dns1.uni-bonn.de 2a00:5ba0:0:1010::83dc:10dcNOERROR, 6 ms, authoritativenoyes / yesrefused-
dns2.uni-bonn.de 131.220.18.138NOERROR, 6 ms, authoritativenoyes / yesrefused-
dns2.uni-bonn.de 2a00:5ba0:0:1001::83dc:128aNOERROR, 6 ms, authoritativenoyes / yesrefused-
dns3.uni-bonn.de 131.220.14.203NOERROR, 5 ms, authoritativenoyes / yesrefused-
dns3.uni-bonn.de 2a00:5ba0:0:1002::83dc:ecbNOERROR, 8 ms, authoritativenoyes / yesrefused-
unibn-dns.uni-koeln.de 134.95.48.166NOERROR, 11 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.
  • ✓ 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

pass

serial 759573206 · primary dns1.uni-bonn.de

Found

Primary (MNAME)
dns1.uni-bonn.de
Contact (RNAME)
dnsadmin.uni-bonn.de
Serial
759573206
Refresh / retry
10800 s / 3600 s
Expire
1209600 s
Negative TTL
10800 s

Serial per nameserver

NameserverSerial
dns1.uni-bonn.de (131.220.16.220)759573206
dns1.uni-bonn.de (2a00:5ba0:0:1010::83dc:10dc)759573206
dns2.uni-bonn.de (131.220.18.138)759573206
dns2.uni-bonn.de (2a00:5ba0:0:1001::83dc:128a)759573206
dns3.uni-bonn.de (131.220.14.203)759573206
dns3.uni-bonn.de (2a00:5ba0:0:1002::83dc:ecb)759573206
unibn-dns.uni-koeln.de (134.95.48.166)759573206

Checks

  • ✓ Serial 759573206 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 3h, retry 1h, expire 14d, negative TTL 3h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns1.uni-bonn.de is one of the listed nameservers.
  • ✓ Contact dnsadmin@uni-bonn.de #25
    The SOA RNAME dnsadmin.uni-bonn.de means dnsadmin@uni-bonn.de.
  • ✓ Counter serial #26
    The serial 759573206 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

17 records at the apex

Found

Read from
131.220.16.220:53
TypeValueTTL
SOAdns1.uni-bonn.de. dnsadmin.uni-bonn.de. 759573206 10800 3600 1209600 1080086400
NSdns1.uni-bonn.de.86400
NSdns2.uni-bonn.de.86400
NSdns3.uni-bonn.de.86400
NSunibn-dns.uni-koeln.de.86400
A194.164.58.145300
AAAA2a01:239:27a:3700::1300
MX100 esa3.rhrz.uni-bonn.de.86400
MX10 esa2.rhrz.uni-bonn.de.86400
MX10 esa1.rhrz.uni-bonn.de.86400
TXT"HARICA-Hf5sRR9sQOLuRwyiShT"3600
TXT"brevo-code:b29074b4de214c8c9b64b5ea53c04c22"3600
TXT"apple-domain-verification=r5q5vPY7h7Wg6Xsx"3600
TXT"google-site-verification=6v-teCoU1YzGJea5IAqVm3H-_rLfhqOusk-WcQ_8JoU"3600
TXT"adobe-idp-site-verification=bd0fa3cf08dfe6bdd630f27c73e21afafa8ab3130adf2e18c3d10fe9811dae7e"3600
TXT"ZA=gzEWqDpBI3Hd1nS0vHm0Ow=="3600
TXT"v=spf1 ip4:131.220.75.223 ip4:194.94.253.25 ~all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, AAAA 5m, 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