hku.nl

Checked 21 October 2026, 21:21 UTC · via 8.8.8.8
!Passed with warnings
25 passed 2 warnings 0 failed 6 info

Registration

info

.nl country-code

Found

TLD
.nl (country-code)
ICANN policies apply
no
Lookup error: https://rdap.sidn.nl/domain/hku.nl returned HTTP 429

Checks

  • i
    .nl 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
    .nl is delegated in the root zone and DNSSEC-signed.
  • i
    Could not be checked
    The RDAP lookup failed, so this could not be checked: https://rdap.sidn.nl/domain/hku.nl returned HTTP 429
    #3

Delegation

warn

leia.hku.nl, ns1.surfnet.nl, quipu.hku.nl, yoda.hku.nl

Found

Parent zone
nl
Delegation from
ns1.dns.nl (194.0.28.53)
NS at the parent
leia.hku.nl, ns1.surfnet.nl, quipu.hku.nl, yoda.hku.nl
NS in the zone
leia.hku.nl, luke.hku.nl, ns1.surfnet.nl, quipu.hku.nl, yoda.hku.nl
NameserverAddressesNetwork (AS)Glue
leia.hku.nl192.87.219.101AS1103 SURFNET-NL - SURF B.V., NL192.87.219.101
luke.hku.nl (zone only)192.87.218.101AS1103 SURFNET-NL - SURF B.V., NL-
ns1.surfnet.nl192.87.106.101 2001:610:1:800a:192:87:106:101AS1103 SURFNET-NL - SURF B.V., NL AS1103 SURFNET-NL - SURF B.V., NL192.87.106.101 2001:610:1:800a:192:87:106:101
quipu.hku.nl192.87.219.67AS1103 SURFNET-NL - SURF B.V., NL192.87.219.67
yoda.hku.nl192.87.219.71 2001:610:a30:19::71AS1103 SURFNET-NL - SURF B.V., NL AS1103 SURFNET-NL - SURF B.V., NL192.87.219.71 2001:610:a30:19::71

Checks

  • ✓ 4 nameservers #6
    Delegated to leia.hku.nl, ns1.surfnet.nl, quipu.hku.nl, yoda.hku.nl.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only in the zone: luke.hku.nl. leia.hku.nl, luke.hku.nl, ns1.surfnet.nl, quipu.hku.nl, yoda.hku.nl report NS leia.hku.nl luke.hku.nl ns1.surfnet.nl quipu.hku.nl yoda.hku.nl.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: leia.hku.nl, quipu.hku.nl, yoda.hku.nl.
  • ✓ 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.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS1103 (SURFNET-NL - SURF B.V., NL): 7 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 .nl
    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: leia.hku.nl, luke.hku.nl, quipu.hku.nl.
    #13

Nameservers

warn

7 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
leia.hku.nl 192.87.219.101NOERROR, 10 ms, authoritativenoyes / yesrefused9.20.29
luke.hku.nl 192.87.218.101NOERROR, 10 ms, authoritativenoyes / yesrefused9.20.29
ns1.surfnet.nl 192.87.106.101NOERROR, 10 ms, authoritativenoyes / yesrefusedThis is a SURFnet nameserver - dns-beheer@surfnet.nl
ns1.surfnet.nl 2001:610:1:800a:192:87:106:101NOERROR, 10 ms, authoritativenoyes / yesrefusedThis is a SURFnet nameserver - dns-beheer@surfnet.nl
quipu.hku.nl 192.87.219.67NOERROR, 11 ms, authoritativenoyes / yesrefused9.20.29
yoda.hku.nl 192.87.219.71NOERROR, 11 ms, authoritativenoyes / yesrefused9.20.29
yoda.hku.nl 2001:610:a30:19::71NOERROR, 11 ms, authoritativenoyes / yesrefused9.20.29

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.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: leia.hku.nl: "9.20.29"; luke.hku.nl: "9.20.29"; quipu.hku.nl: "9.20.29"; yoda.hku.nl: "9.20.29". 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

pass

serial 2026102015 · primary yoda.hku.nl

Found

Primary (MNAME)
yoda.hku.nl
Contact (RNAME)
postmaster.yoda.hku.nl
Serial
2026102015
Refresh / retry
14400 s / 7200 s
Expire
604800 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
leia.hku.nl (192.87.219.101)2026102015
luke.hku.nl (192.87.218.101)2026102015
ns1.surfnet.nl (192.87.106.101)2026102015
ns1.surfnet.nl (2001:610:1:800a:192:87:106:101)2026102015
quipu.hku.nl (192.87.219.67)2026102015
yoda.hku.nl (192.87.219.71)2026102015
yoda.hku.nl (2001:610:a30:19::71)2026102015

Checks

  • ✓ Serial 2026102015 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 4h, retry 2h, expire 7d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver yoda.hku.nl is one of the listed nameservers.
  • ✓ Contact postmaster@yoda.hku.nl #25
    The SOA RNAME postmaster.yoda.hku.nl means postmaster@yoda.hku.nl.
  • ✓ Date-based serial #26
    The serial 2026102015 follows the YYYYMMDDnn convention (2026-10-20).

DNSSEC

info

Signed, DS published at parent

Found

Validated by resolver
yes
Denial of existence
NSEC
Signatures valid until
4 November 2026

DS at the parent

Key tagAlgorithmDigestMatches a key
63646ECDSAP256SHA256 (13)SHA256 CC8DAFC24DF7474B…yes

DNSKEY in the zone

Key tagRoleAlgorithm
63646KSK (257)ECDSAP256SHA256 (13)

Checks

  • ✓ Signed and validated #27
    The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
  • ✓ DS matches a key #28
    The DS record at the parent matches a key in the zone: key tag 63646 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • ✓ Signatures valid until 2026-11-04 #30
    The earliest DNSKEY/SOA signature expires at 2026-11-04 04:42 UTC.
  • i
    NSEC
    The zone uses NSEC, so its full contents can be listed by walking the NSEC chain. That is fine unless the names are sensitive.
    #31

Records

pass

17 records at the apex

Found

Read from
192.87.219.101:53
TypeValueTTL
SOAyoda.hku.nl. postmaster.yoda.hku.nl. 2026102015 14400 7200 604800 360021600
NSquipu.hku.nl.21600
NSluke.hku.nl.21600
NSns1.surfnet.nl.21600
NSleia.hku.nl.21600
NSyoda.hku.nl.21600
A192.87.219.16521600
MX10 hku-nl.mail.protection.outlook.com.21600
TXT"atlassian-domain-verification=UZE8qrqhgKTJ3DKHVeYdAHFNEXs7E4Gbe7aBqPLR0voaY22awkxvxDnQiGPiWtVf"21600
TXT"apple-domain-verification=5khbm4kg8W2QpFk2"21600
TXT"facebook-domain-verification=el1p6tmcagn39kk2lg20moo6f3umpy"21600
TXT"atlassian-sending-domain-verification=bd160452-1554-4f8a-9c5e-6bca75793e62"21600
TXT"HARICA-NADOQbNbmmKePlxOmeT"21600
TXT"v=spf1 ip4:192.87.219.71 ip4:20.160.243.164 ip4:136.144.213.2 ip4:145.107.223.250 ip4:192.87.219.164 ip4:192.87.219.240 ip4:35.204.242.219 ip4:35.204.41.40 " "ip6:2001:610:a30:19::71 include:_spf.spotler.email include:email.activetickets.com include:_spf.salesforce.com include:mailswitch.nl include:spf.protection.outlook.com -all"21600
CAA0 issue "harica.gr"21600
CAA0 issuewild "harica.gr"21600
CAA0 issuemail "harica.gr"21600

Checks

  • ✓ TTLs within range #32
    TTLs: A 6h, MX 6h, NS 6h. The NS TTL at the parent is 1h and in the zone 6h; 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.
  • ✓ CAA restricts issuance #35
    Certificates may be issued by: harica.gr.