astron.nl

Checked 21 October 2026, 20:45 UTC · via 8.8.8.8
!Passed with warnings
26 passed 2 warnings 0 failed 5 info

Registration

info

.nl country-code

Found

TLD
.nl (country-code)
ICANN policies apply
no
Lookup error: https://rdap.sidn.nl/domain/astron.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/astron.nl returned HTTP 429
    #3

Delegation

info

dns1.astron.nl, dns2.astron.nl, ns1.surfnet.nl

Found

Parent zone
nl
Delegation from
ns1.dns.nl (194.0.28.53)
NS at the parent
dns1.astron.nl, dns2.astron.nl, ns1.surfnet.nl
NS in the zone
dns1.astron.nl, dns2.astron.nl, ns1.surfnet.nl
NameserverAddressesNetwork (AS)Glue
dns1.astron.nl195.169.155.28 2001:610:9b8:32::28AS1103 SURFNET-NL - SURF B.V., NL AS1103 SURFNET-NL - SURF B.V., NL195.169.155.28 2001:610:9b8:32::28
dns2.astron.nl145.124.51.7 2001:610:9b8:510::7AS1103 SURFNET-NL - SURF B.V., NL AS1103 SURFNET-NL - SURF B.V., NL145.124.51.7 2001:610:9b8:510::7
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

Checks

  • ✓ 3 nameservers #6
    Delegated to dns1.astron.nl, dns2.astron.nl, ns1.surfnet.nl.
  • ✓ 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: dns1.astron.nl, dns2.astron.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): 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.

Nameservers

warn

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns1.astron.nl 195.169.155.28NOERROR, 12 ms, authoritativenoyes / yesrefused9.20.18-1ubuntu2-Ubuntu
dns1.astron.nl 2001:610:9b8:32::28NOERROR, 12 ms, authoritativenoyes / yesrefused9.20.18-1ubuntu2-Ubuntu
dns2.astron.nl 145.124.51.7NOERROR, 12 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.9.16
dns2.astron.nl 2001:610:9b8:510::7NOERROR, 12 ms, authoritativenoyes / yesrefusedPowerDNS Authoritative Server 4.9.16
ns1.surfnet.nl 192.87.106.101NOERROR, 9 ms, authoritativenoyes / yesrefusedThis is a SURFnet nameserver - dns-beheer@surfnet.nl
ns1.surfnet.nl 2001:610:1:800a:192:87:106:101NOERROR, 9 ms, authoritativenoyes / yesrefusedThis is a SURFnet nameserver - dns-beheer@surfnet.nl

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.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: dns1.astron.nl: "9.20.18-1ubuntu2-Ubuntu"; dns2.astron.nl: "PowerDNS Authoritative Server 4.9.16". 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

warn

serial 2026100500 · primary dns1.astron.nl

Found

Primary (MNAME)
dns1.astron.nl
Contact (RNAME)
servicedesk.astron.nl
Serial
2026100500
Refresh / retry
3600 s / 3600 s
Expire
604800 s
Negative TTL
300 s

Serial per nameserver

NameserverSerial
dns1.astron.nl (195.169.155.28)2026100500
dns1.astron.nl (2001:610:9b8:32::28)2026100500
dns2.astron.nl (145.124.51.7)2026100500
dns2.astron.nl (2001:610:9b8:510::7)2026100500
ns1.surfnet.nl (192.87.106.101)2026100500
ns1.surfnet.nl (2001:610:1:800a:192:87:106:101)2026100500

Checks

  • ✓ Serial 2026100500 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    retry 1h should be shorter than refresh 1h. Current values: refresh 1h, retry 1h, expire 7d, negative TTL 5m.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns1.astron.nl is one of the listed nameservers.
  • ✓ Contact servicedesk@astron.nl #25
    The SOA RNAME servicedesk.astron.nl means servicedesk@astron.nl.
  • ✓ Date-based serial #26
    The serial 2026100500 follows the YYYYMMDDnn convention (2026-10-05).

DNSSEC

info

Signed, DS published at parent

Found

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

DS at the parent

Key tagAlgorithmDigestMatches a key
8201ECDSAP256SHA256 (13)SHA256 6EA1D3B98AEF58D1…yes

DNSKEY in the zone

Key tagRoleAlgorithm
8201KSK (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 8201 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • ✓ Signatures valid until 2026-11-03 #30
    The earliest DNSKEY/SOA signature expires at 2026-11-03 17:02 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
195.169.155.28:53
TypeValueTTL
SOAdns1.astron.nl. servicedesk.astron.nl. 2026100500 3600 3600 604800 300300
NSns1.surfnet.nl.300
NSdns1.astron.nl.300
NSdns2.astron.nl.300
A145.124.48.19300
AAAA2001:610:9b8:480::19300
MX0 astron-nl.mail.protection.outlook.com.300
TXT"apple-domain-verification=TQKiG8rPl0kLKoyC"300
TXT"DomainVerification=KYSSARPYEUQUS3VT4XZUZ38M3C5IS4Z93GOQDCDLLT3Q2VUCW86XTZA4IXSVPMQJ"300
TXT"miro-verification=cc9850732ef172fcb2d18a2ebf65c21019be34e8"300
TXT"MS=ms89177969"300
TXT"v=spf1 include:c05aw084hi.powerspf.com ~all"300
TXT"have-i-been-pwned-verification=40a66e40dd2faedbc7271c230f65c913"300
TXT"google-site-verification=OVXVoo7ts70_667CpiuvrduErxwZlav2x3mbXIXMl9o"300
CAA0 issue "letsencrypt.org"300
CAA0 issue "harica.gr"300
CAA0 issue "sectigo.com"300

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, AAAA 5m, MX 5m, NS 5m. The NS TTL at the parent is 1h and in the zone 5m; 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: letsencrypt.org, harica.gr, sectigo.com.