uos.de

Checked 22 October 2026, 00:50 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

dns-1.serv.uni-osnabrueck.de, dns-2.serv.uni-osnabrueck.de, dns-3.serv.uni-osnabrueck.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.serv.uni-osnabrueck.de, dns-2.serv.uni-osnabrueck.de, dns-3.serv.uni-osnabrueck.de
NS in the zone
dns-1.serv.uni-osnabrueck.de, dns-2.serv.uni-osnabrueck.de, dns-3.serv.uni-osnabrueck.de
NameserverAddressesNetwork (AS)Glue
dns-1.serv.uni-osnabrueck.de131.173.245.1 2001:638:508:f50::83ad:f501AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE131.173.245.1 2001:638:508:f50::83ad:f501
dns-2.serv.uni-osnabrueck.de141.41.241.52AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE141.41.241.52
dns-3.serv.uni-osnabrueck.de141.70.192.33 2001:7c7:2441:853::5353AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE141.70.192.33 2001:7c7:2441:853::5353

Checks

  • ✓ 3 nameservers #6
    Delegated to dns-1.serv.uni-osnabrueck.de, dns-2.serv.uni-osnabrueck.de, dns-3.serv.uni-osnabrueck.de.
  • ✓ 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 2 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS553 (BELWUE - Universitaet Stuttgart, DE): 2 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: dns-2.serv.uni-osnabrueck.de.
    #13

Nameservers

pass

5 of 5 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.serv.uni-osnabrueck.de 131.173.245.1NOERROR, 16 ms, authoritativenoyes / yesrefused-
dns-1.serv.uni-osnabrueck.de 2001:638:508:f50::83ad:f501NOERROR, 16 ms, authoritativenoyes / yesrefused-
dns-2.serv.uni-osnabrueck.de 141.41.241.52NOERROR, 11 ms, authoritativenoyes / yesrefused-
dns-3.serv.uni-osnabrueck.de 141.70.192.33NOERROR, 8 ms, authoritativenoyes / yesrefused-
dns-3.serv.uni-osnabrueck.de 2001:7c7:2441:853::5353NOERROR, 7 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 5 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 803578715 · primary dns-1.serv.uni-osnabrueck.de

Found

Primary (MNAME)
dns-1.serv.uni-osnabrueck.de
Contact (RNAME)
dnsadmin.uni-osnabrueck.de
Serial
803578715
Refresh / retry
3602 s / 1802 s
Expire
1209600 s
Negative TTL
1202 s

Serial per nameserver

NameserverSerial
dns-1.serv.uni-osnabrueck.de (131.173.245.1)803578715
dns-1.serv.uni-osnabrueck.de (2001:638:508:f50::83ad:f501)803578715
dns-2.serv.uni-osnabrueck.de (141.41.241.52)803578715
dns-3.serv.uni-osnabrueck.de (141.70.192.33)803578715
dns-3.serv.uni-osnabrueck.de (2001:7c7:2441:853::5353)803578715

Checks

  • ✓ Serial 803578715 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 1h0m2s, retry 30m2s, expire 14d, negative TTL 20m2s.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns-1.serv.uni-osnabrueck.de is one of the listed nameservers.
  • ✓ Contact dnsadmin@uni-osnabrueck.de #25
    The SOA RNAME dnsadmin.uni-osnabrueck.de means dnsadmin@uni-osnabrueck.de.
  • ✓ Counter serial #26
    The serial 803578715 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

12 records at the apex

Found

Read from
131.173.245.1:53
TypeValueTTL
SOAdns-1.serv.uni-osnabrueck.de. dnsadmin.uni-osnabrueck.de. 803578715 3602 1802 1209600 12021801
NSdns-2.serv.uni-osnabrueck.de.1801
NSdns-1.serv.uni-osnabrueck.de.1801
NSdns-3.serv.uni-osnabrueck.de.1801
A131.173.17.2031801
AAAA2001:638:508:100::83ad:11cb1801
MX60 a2411.mx.srv.dfn.de.1801
MX60 c2411.mx.srv.dfn.de.1801
MX60 b2411.mx.srv.dfn.de.1801
TXT"v=spf1 redirect=uni-osnabrueck.de"1801
TXT"MS=2557A9E7068D05C3D530DB8AAEA6B5A34C0E38A5"1801
TXT"fefa731e-c4ed-4a97-bf74-e0fa08211653"1801

Checks

  • ✓ TTLs within range #32
    TTLs: A 30m1s, AAAA 30m1s, MX 30m1s, NS 30m1s. The NS TTL at the parent is 1d and in the zone 30m1s; resolvers may use either.
  • ✓ No CNAME at the apex #33
    The zone apex has no CNAME record.
  • i
    Wildcard record
    A random name under the zone resolves, so there is a wildcard (*) record. Typos and non-existent hosts resolve too, which can confuse mail and certificate checks.
    #34
  • 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