liacs.nl

.nl country-code

Found

TLD

.nl (country-code)

ICANN policies apply

no

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/liacs.nl returned HTTP 429

  #3

ns1.surfnet.nl, ns2.surfnet.nl, ns3.surfnet.nl

Found

Parent zone

nl

Delegation from

ns1.dns.nl (194.0.28.53)

NS at the parent

ns1.surfnet.nl, ns2.surfnet.nl, ns3.surfnet.nl

NS in the zone

ns1.surfnet.nl, ns2.surfnet.nl, ns3.surfnet.nl

Checks

• ✓ 3 nameservers #6

  Delegated to ns1.surfnet.nl, ns2.surfnet.nl, ns3.surfnet.nl.
• ✓ 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 3 IPv6 /48s.
• i

  All nameservers in one AS

  All nameserver addresses are announced by one network operator (AS1103 (SURFNET-NL - SURF B.V., NL): 6 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
• ✓ All reachable over IPv6 #13

  Every nameserver has an IPv6 address.

6 of 6 addresses answer authoritatively

Found

Checks

• ✓ All respond #14

  All 6 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: ns1.surfnet.nl: "This is a SURFnet nameserver - dns-beheer@surfnet.nl"; ns2.surfnet.nl: "This is a SURFnet nameserver - dns-beheer@surfnet.nl"; ns3.surfnet.nl: "This is a SURFnet nameserver - dns-beheer@surfnet.nl".

  #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.

serial 2026101901 · primary noc.liacs.nl

Found

Primary (MNAME)

noc.liacs.nl

Contact (RNAME)

rel.liacs.nl

Serial

2026101901

Refresh / retry

14400 s / 7200 s

Expire

1209600 s

Negative TTL

86400 s

Serial per nameserver

Checks

• ✓ Serial 2026101901 everywhere #22

  All nameservers serve the same version of the zone.
• ✓ Timers within recommendations #23

  SOA refresh 4h, retry 2h, expire 14d, negative TTL 1d.
• i

  Hidden master

  The primary nameserver noc.liacs.nl is not listed as a nameserver: a hidden master that only feeds the public secondaries. That is a common setup; make sure it is not reachable for zone transfers from outside.

  #24
• ✓ Contact rel@liacs.nl #25

  The SOA RNAME rel.liacs.nl means rel@liacs.nl.
• ✓ Date-based serial #26

  The serial 2026101901 follows the YYYYMMDDnn convention (2026-10-19).