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DNS Tool
Engineer's DNS Intelligence Report
Generated 12 Feb 2026, 09:28 UTC
Duration 48.6s
Version v26.12.28
Integrity 647704e542e3d88607b4db6db547c2b67d46162199c3742f3a3e675da83d8d282dcac71d7ad2f263908ffd1fadd4ba62984870ac583d97b0556f83f29066c920
Subject Domain
nlnetlabs.nl

Engineer's DNS Intelligence Report

nlnetlabs.nl
12 Feb 2026, 09:28 UTC · 48.6s ·v26.12.28 · SHA-3-512: 6477✱✱✱✱ Verify
Executive Methodology
Recon Mode Snapshot Re-analyze New Domain
Footprint 1 SaaS Service
DNS Security & Trust Posture
Risk Level: Medium Risk Monitoring
4 protocols configured, 3 not configured DMARC is in monitoring mode (p=none) with aggregate reporting active — this appears to be a deliberate deployment phase before enforcement Why we go beyond letter grades
1 monitoring
Email Spoofing
Partial
Brand Impersonation
Not Setup
DNS Tampering
Protected
Certificate Control
Open
Monitoring
DMARC in monitoring mode (p=none)
Configured
SPF (~all), DKIM, DANE, DNSSEC
Not Configured
MTA-STS, TLS-RPT, CAA
Priority Actions 4 total Achievable posture: Low Risk
High Escalate DMARC from monitoring to enforcement

Change your DMARC policy from p=none to p=quarantine (then p=reject). Review your DMARC aggregate reports first to ensure legitimate senders pass authentication.

_dmarc.nlnetlabs.nl TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@nlnetlabs.nl"
RFC 7489 §6.3
Medium Deploy MTA-STS policy

Publish an MTA-STS DNS record and host a policy file at https://mta-sts.nlnetlabs.nl/.well-known/mta-sts.txt. This tells senders to require TLS when delivering mail to your domain.

_mta-sts.nlnetlabs.nl TXT "v=STSv1; id=20240101"
RFC 8461 §3
Low Add CAA records

Publish CAA DNS records to restrict which Certificate Authorities can issue TLS certificates for your web services (HTTPS). Your email transport already uses DANE, which validates mail server certificates via DNSSEC without relying on CAs — so CAA is primarily relevant to your web-facing certificates.

nlnetlabs.nl CAA 0 issue "letsencrypt.org"
RFC 8659 §4
Low Configure TLS-RPT reporting

Your domain has DNSSEC + DANE — the strongest email transport security available. TLS-RPT adds operational visibility by reporting when sending servers fail DANE validation or encounter STARTTLS issues delivering to your MX hosts. It does not add security — it monitors the security you already have.

_smtp._tls.nlnetlabs.nl TXT "v=TLSRPTv1; rua=mailto:tls-reports@nlnetlabs.nl"
RFC 8460 §3
Registrar (WHOIS) OBSERVED LIVE
Prolocation B.V.
Where domain was purchased
Email Service Provider OBSERVED
Google Workspace
Email: Monitoring
Web Hosting
Unknown
Where website is hosted
DNS Hosting OBSERVED
Unknown
Where DNS records are edited
Email Security Methodology Can this domain be impersonated by email? Partially
Verdict: Partial email authentication configured — some spoofed messages may be delivered. DMARC is in monitoring mode (p=none).

SPF Record RFC 7208 §4 Verified

Does this domain declare who may send email on its behalf? Yes
Success ~all 2/10 lookups

SPF valid with industry-standard soft fail (~all), 2/10 lookups

v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
RFC 7208 Conformant — This SPF record conforms to the syntax and semantics defined in RFC 7208 §4.
RFC Failure Mode: Unlike DMARC (where unknown tags are silently ignored per RFC 7489 §6.3), SPF with unrecognized mechanisms produces a PermError per RFC 7208 §4.6 — the record fails loudly rather than silently.
Related CVEs: CVE-2024-7208 (multi-tenant domain spoofing), CVE-2024-7209 (shared SPF exploitation), CVE-2023-51764 (SMTP smuggling bypasses SPF)
~all is the industry standard. Google, Apple, and most providers default to soft fail. CISA (BOD 18-01) and RFC 7489 confirm that DMARC policy — not SPF alone — is the primary enforcement control. Using ~all allows DKIM to be evaluated before a DMARC decision is made. This domain has DMARC p=none (monitoring only). Enforcing quarantine or reject is recommended to gain real protection.

DMARC Policy RFC 7489 §6.3 Verified

Are spoofed emails rejected or quarantined? Monitoring only
Warning p=none

DMARC in monitoring mode (p=none) - spoofed mail still delivered, no enforcement

v=DMARC1; p=none; sp=none; psd=n; rua=mailto:dmarc-feedback@nlnetlabs.nl
Policy p=none provides no protection - spoofed emails reach inboxes
Advanced cryptographic posture detected. DMARC is in monitoring mode (p=none) with aggregate reporting active — this appears to be a deliberate deployment phase before enforcement
Escalate DMARC from monitoring to enforcement:
_dmarc.nlnetlabs.nl TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@nlnetlabs.nl"
RFC 7489 Present — DMARC record published per RFC 7489 §6.3.
DMARCbis (Pending): draft-ietf-dmarc-dmarcbis will elevate DMARC to Standards Track, obsolete RFC 7489, replace pct= with t= (testing flag), add np= (non-existent subdomain policy), and mandate DNS tree walk for policy discovery instead of the Public Suffix List.
Related CVEs: CVE-2024-49040 (Exchange sender spoofing), CVE-2024-7208 (multi-tenant DMARC bypass)

DKIM Records RFC 6376 §3.6 Verified

Are outbound emails cryptographically signed? Yes — verified
Found

Found DKIM records for 2 selector(s)

DKIM key in test mode (t=y per RFC 6376 §3.6.1) — verifiers should treat failures as unsigned, remove t=y for production
default._domainkey
v=DKIM1; g=*; k=rsa; t=y;p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDOBxkIlNsk1fVhUO8fZs6qJV6/ZFEsltVIuTHDUn1dQXOSqo04SCOXiuRgsFzxKKAOqZKksjEdxzcGI7UIakfyzHEeoAeeJCrIQoY3NcTOm6Z4ak5X24X8dPIi2075YwFAHiwELthtgwtrvUpWr6U0KBmEeXtyQ4nk++HR2asJIQIDAQAB
google._domainkey Google Workspace
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAhfvuanQm2kCz1VQ9gSR4yfap9BonWGMMo56dnGVCfySlaNVqMumJTferAsSn5HnlciPA6LJ46i28kX75jY9P1K9BBA4vwBrlhg9nS+LjgdbKiynnyq92ARWYsVUrdzmdQNgu3K4OjzFHEQXLsCpRSrPs4X/UiaUufabV/EMRD7xp5GhE6arl3inx7B65gOifzMg241EQM6bliIlt6Q8wTanhA8kbzBvJ5MT/9rryGX9X7msJ+v9xYEybiPZyGwnhnI6LMewcHzxtK4LFoYTrb0NOSK+tueth4Vhdz1TBbFwIT9IykxL6+75MqrQKSFzXAwg432yHkpian+8Z/4jAkQIDAQAB
RFC 6376 Conformant — DKIM keys and signatures conform to RFC 6376 §3.6 (Internet Standard).
Known Vulnerabilities: DKIM l= tag body length vulnerability (attacker appends unsigned content to signed mail), weak key exploitation (keys below 1024-bit are cryptographically breakable per RFC 6376 §3.3.3), DKIM replay attacks (re-sending legitimately signed messages at scale)

MTA-STS RFC 8461 §3 Verified

Can attackers downgrade SMTP to intercept mail? Not prevented
Warning

No MTA-STS record found

MTA-STS policy enforcement is evaluated in Mail Transport Security below.

TLS-RPT RFC 8460 §3 Verified

Will failures in TLS delivery be reported? No reporting
Warning

No TLS-RPT record found

DANE / TLSA Verified Recon Methodology Can mail servers establish identity without a public CA? Yes
RFC 7672 §3 RFC 6698 §2 3/3 MX

DANE configured — TLSA records found for all 3 MX hosts

MX Host Usage Selector Match Certificate Data
mxext2.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 e41cc7633029afdba53744d7e5fc31ef507e592de9dfb33557bf3b9a79239446
mxext2.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 4758af6f02dfb5dc8795fa402e77a8a0486af5e85d2ca60c294476aadc40b220
mxext2.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 996ad31d65e03f038b8ec950f6f26611529da03e3a283e4400cba2edd04b8a88
mxext3.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 e41cc7633029afdba53744d7e5fc31ef507e592de9dfb33557bf3b9a79239446
mxext3.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 996ad31d65e03f038b8ec950f6f26611529da03e3a283e4400cba2edd04b8a88
mxext3.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 4758af6f02dfb5dc8795fa402e77a8a0486af5e85d2ca60c294476aadc40b220
mxext1.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 e41cc7633029afdba53744d7e5fc31ef507e592de9dfb33557bf3b9a79239446
mxext1.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 4758af6f02dfb5dc8795fa402e77a8a0486af5e85d2ca60c294476aadc40b220
mxext1.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 996ad31d65e03f038b8ec950f6f26611529da03e3a283e4400cba2edd04b8a88
Email Transport Security

Two mechanisms protect email in transit. DANE is the primary standard; MTA-STS is the alternative for domains that cannot deploy DNSSEC:

  • DNSSEC + DANE (RFC 7672) — Cryptographic chain of trust from DNS root to mail server certificate. Eliminates reliance on certificate authorities. No trust-on-first-use weakness. Requires DNSSEC.
  • MTA-STS (RFC 8461) — HTTPS-based policy requiring TLS for mail delivery. Works without DNSSEC but relies on CA trust and is vulnerable on first use (§10). Created for domains where “deploying DNSSEC is undesirable or impractical” (§2).
This domain uses DNSSEC + DANE — the strongest cryptographic transport security. DANE binds TLS certificates to DNSSEC-signed DNS records, creating a verifiable chain of trust from root to mail server (RFC 7672 §1.3). MTA-STS could complement this for senders that don't validate DNSSEC, but DANE alone provides the highest level of protection available.

Industry trend: Microsoft Exchange Online enforces inbound DANE with DNSSEC (GA October 2024), and providers like Proton Mail and Fastmail also support DANE. Google Workspace does not support DANE and relies on MTA-STS. Both mechanisms coexist because DANE is backward-compatible — senders skip the check if the domain isn't DNSSEC-signed (RFC 7672 §1.3).

Brand Security Can this brand be convincingly faked?
Verdict: No brand protection configured. Any CA can issue certificates and no brand logo verification in place.

BIMI BIMI Spec Verified Warning

Is the brand identity verified and displayed in inboxes? No

No BIMI record found

CAA RFC 8659 §4 Verified Warning

Does this domain restrict who can issue TLS certificates? No

No CAA records found - any CA can issue certificates

Mail Transport Security Beta Is mail transport encrypted and verified? Not Enforced

Transport security inferred from 1 DNS signal(s)

Direct SMTP probe unavailable (port 25 blocked). Transport security inferred from DNS policy records and provider capabilities.
Transport Security Signals:
  • DANE/TLSA records published — mail servers pin TLS certificates via DNSSEC
SMTP port 25 may be blocked by hosting provider — this is common for cloud platforms
Infrastructure Intelligence Who hosts this domain and what services power it? Direct

ASN / Network Success

Resolved 1 unique ASN(s) across 2 IP address(es)

ASNNameCountry
AS24940 DE
IPv4 Mappings:
128.140.76.106 → AS24940 (128.140.0.0/17)
IPv6 Mappings:
2a01:4f8:c0c:cdfa::1 → AS24940 (2a01:4f8::/32)

Edge / CDN Success

Domain appears to use direct origin hosting

SaaS TXT Footprint Success 1 service

1 SaaS service(s) detected via TXT record verification

Detects SaaS services that leave DNS TXT verification records (e.g., domain ownership proofs). Does not detect all SaaS platforms — only those indicated by DNS.

ServiceVerification Record
1Password 1password-site-verification=QAXPQAT46NGABHYNFZ5HGZUELQ
Domain Security Methodology Can DNS responses be tampered with in transit?

DNSSEC RFC 4033 §2 Verified Signed RSA/SHA-256

DNSSEC fully configured and validated — AD (Authenticated Data) flag set by resolver 8.8.8.8 confirming cryptographic chain of trust from root to zone (RFC 4035 §3.2.3)

Chain of trust: Root → TLD → Domain. DNS responses are authenticated and tamper-proof.
AD Flag: Validated - Resolver (8.8.8.8) confirmed cryptographic signatures
DS Record (at registrar):
50602 8 2 FA8EE175C47325F4BD46D8A4083C3EBEB11C977D689069F2B41F1A29B22446B1

NS Delegation Verified

3 nameserver(s) configured

Nameservers: anyns.pch.net ns.nlnetlabs.nl ns5.sidn.nl
Multi-Resolver Verification Recon: Consensus reached - 4 resolvers (Cloudflare, Google, Quad9, OpenDNS, DNS4EU) agree on DNS records
Traffic & Routing Where does this domain's traffic actually terminate?

AIPv4 Address

128.140.76.106
Where the domain points for web traffic

AAAAIPv6 Address

2a01:4f8:c0c:cdfa::1
IPv6 ready

MXMail Servers

10 mxext1.mailbox.org.
10 mxext2.mailbox.org.
20 mxext3.mailbox.org.
Priority + mail server for email delivery
Google Workspace

SRVServices

_autodiscover._tcp: 0 0 443 mailbox.org.
_xmpp-client._tcp: 5 0 5222 open.nlnetlabs.nl.
SIP, XMPP, or other service endpoints
Web: Reachable (1 IPv4, 1 IPv6) Mail: 3 servers Services: 2 endpoints
Subdomain Discovery RFC 6962 Recon LIVE What subdomains and infrastructure are exposed in certificate logs? 282 subdomains discovered
How did we find these?
Certificate Transparency Logs Unavailable The results below are from DNS probing only and may be significantly incomplete. CT logs typically reveal hundreds or thousands of additional subdomains via certificate issuance history (RFC 6962).
Re-Analyze to Retry CT Lookup
2795 certificates analyzed current expired Source: Certificate Transparency Logs
Subdomain Source Status Provider / CNAME Certificates First Seen Issuer(s)
CT Log Expired — 11 — —
CT Log Expired — 2 — —
CT Log Expired — 4 — —
CT Log Expired — 2 — —
CT Log Expired — 48 — —
CT Log Expired — 50 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 116 — —
CT Log Expired — 4 — —
CT Log Expired — 43 — —
CT Log Expired — 116 — —
CT Log Expired — 4 — —
CT Log Expired — 26 — —
CT Log Expired — 4 — —
CT Log Expired — 10 — —
CT Log Expired — 2 — —
CT Log Expired — 6 — —
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CT Log Expired — 4 — —
CT Log Expired — 2 — —
CT Log Expired — 116 — —
CT Log Expired — 22 — —
CT Log Expired — 2 — —
CT Log Expired — 78 — —
CT Log Expired — 68 — —
CT Log Expired — 18 — —
CT Log Expired — 4 — —
CT Log Expired — 10 — —
CT Log Expired — 10 — —
CT Log Expired — 48 — —
CT Log Expired — 2 — —
CT Log Expired — 34 — —
CT Log Expired — 24 — —
CT Log Expired — 2 — —
CT Log Expired — 105 — —
CT Log Expired — 90 — —
CT Log Expired — 90 — —
CT Log Expired — 104 — —
CT Log Expired — 86 — —
CT Log Expired — 6 — —
CT Log Expired — 114 — —
CT Log Expired — 22 — —
CT Log Expired — 100 — —
CT Log Expired — 24 — —
CT Log Expired — 116 — —
CT Log Expired — 91 — —
CT Log Expired — 116 — —
CT Log Expired — 40 — —
CT Log Expired — 2 — —
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CT Log Expired — 4 — —
CT Log Expired — 2 — —
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CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
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CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 4 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
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CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
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CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
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CT Log Expired — 2 — —
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CT Log Expired — 2 — —
CT Log Expired — 1 — —
CT Log Expired — 109 — —
CT Log Expired — 2 — —
CT Log Expired — 30 — —
CT Log Expired — 8 — —
CT Log Expired — 8 — —
CT Log Expired — 20 — —
CT Log Expired — 12 — —
CT Log Expired — 10 — —
CT Log Expired — 2 — —
CT Log Expired — 26 — —
CT Log Expired — 36 — —
CT Log Expired — 74 — —
CT Log Expired — 72 — —
CT Log Expired — 50 — —
CT Log Expired — 21 — —
CT Log Expired — 24 — —
CT Log Expired — 2 — —
CT Log Expired — 68 — —
CT Log Expired — 2 — —
CT Log Expired — 116 — —
CT Log Expired — 44 — —
CT Log Expired — 18 — —
CT Log Expired — 87 — —
CT Log Expired — 12 — —
CT Log Expired — 116 — —
CT Log Expired — 52 — —
CT Log Expired — 80 — —
CT Log Expired — 38 — —
CT Log Expired — 14 — —
CT Log Expired — 6 — —
CT Log Expired — 4 — —
CT Log Expired — 116 — —
CT Log Expired — 8 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 116 — —
CT Log Expired — 26 — —
CT Log Expired — 70 — —
CT Log Expired — 4 — —
CT Log Expired — 111 — —
CT Log Expired — 10 — —
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CT Log Expired — 12 — —
CT Log Expired — 10 — —
CT Log Expired — 2 — —
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CT Log Expired — 5 — —
CT Log Expired — 51 — —
CT Log Expired — 14 — —
CT Log Expired — 2 — —
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CT Log Expired — 14 — —
CT Log Expired — 62 — —
CT Log Expired — 8 — —
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CT Log Expired — 26 — —
CT Log Expired — 6 — —
CT Log Expired — 120 — —
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CT Log Expired — 50 — —
CT Log Expired — 6 — —
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CT Log Expired — 18 — —
CT Log Expired — 26 — —
CT Log Expired — 10 — —
CT Log Expired — 116 — —
CT Log Expired — 116 — —
CT Log Expired — 8 — —
CT Log Expired — 2 — —
CT Log Expired — 41 — —
CT Log Expired — 14 — —
CT Log Expired — 116 — —
CT Log Expired — 4 — —
CT Log Expired — 119 — —
CT Log Expired — 48 — —
CT Log Expired — 2 — —
CT Log Expired — 24 — —
CT Log Expired — 2 — —
CT Log Expired — 19 — —
CT Log Expired — 2 — —
CT Log Expired — 48 — —
CT Log Expired — 48 — —
CT Log Expired — 48 — —
CT Log Expired — 4 — —
CT Log Expired — 13 — —
CT Log Expired — 108 — —
CT Log Expired — 2 — —
CT Log Expired — 8 — —
CT Log Expired — 116 — —
CT Log Expired — 116 — —
CT Log Expired — 68 — —
CT Log Expired — 72 — —
CT Log Expired — 2 — —
CT Log Expired — 78 — —
CT Log Expired — 90 — —
CT Log Expired — 135 — —
CT Log Expired — 48 — —
CT Log Expired — 4 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 4 — —
CT Log Expired — 10 — —
CT Log Expired — 6 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 4 — —
CT Log Expired — 19 — —
CT Log Expired — 46 — —
CT Log Expired — 14 — —
CT Log Expired — 2 — —
CT Log Expired — 4 — —
CT Log Expired — 2 — —
CT Log Expired — 2 — —
CT Log Expired — 8 — —
CT Log Expired — 8 — —
CT Log Expired — 2 — —
CT Log Expired — 8 — —
CT Log Expired — 116 — —
CT Log Expired — 8 — —
CT Log Expired — 24 — —
Export Recon (CSV)
Δ No Propagation Issues: All DNS records are synchronized between resolver and authoritative nameserver.
DNS Intelligence What does DNS look like right now — and what changed over time?
DNS Evidence Diff Side-by-side comparison
Resolver Records (Public DNS cache)
Authoritative Records (Source of truth)
A Synchronized 1 / 1 records
128.140.76.106
128.140.76.106
AAAA Synchronized 1 / 1 records
2a01:4f8:c0c:cdfa::1
2a01:4f8:c0c:cdfa::1
CAA RFC 8659 §4 0 / 0 records
No records
No records
DMARC _dmarc.nlnetlabs.nl RFC 7489 §6.3 Synchronized 1 / 1 records
v=DMARC1; p=none; sp=none; psd=n; rua=mailto:dmarc-feedback@nlnetlabs.nl
v=DMARC1; p=none; sp=none; psd=n; rua=mailto:dmarc-feedback@nlnetlabs.nl
MX RFC 5321 Synchronized 3 / 3 records
10 mxext1.mailbox.org.
10 mxext1.mailbox.org.
10 mxext2.mailbox.org.
20 mxext3.mailbox.org.
20 mxext3.mailbox.org.
10 mxext2.mailbox.org.
NS RFC 1035 Synchronized 3 / 3 records
ns.nlnetlabs.nl.
ns.nlnetlabs.nl.
anyns.pch.net.
anyns.pch.net.
ns5.sidn.nl.
ns5.sidn.nl.
SOA RFC 1035 Synchronized 1 / 1 records
ns.nlnetlabs.nl. hostmaster.nlnetlabs.nl. 2026020100 28800 7200 604800 240
ns.nlnetlabs.nl. hostmaster.nlnetlabs.nl. 2026020100 28800 7200 604800 240
TXT RFC 7208 §4 Synchronized 3 / 3 records
v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
Stichting NLnet Labs zone
Stichting NLnet Labs zone
1password-site-verification=QAXPQAT46NGABHYNFZ5HGZUELQ
1password-site-verification=QAXPQAT46NGABHYNFZ5HGZUELQ
DNS History Timeline BETA
Your key is sent directly to SecurityTrails and is never stored on our servers. Get an API key
DNS History Timeline BETA

When was a record added, removed, or changed — and could that change be the problem?

Analyze Another Domain

Confirm Your Email Configuration

This tool analyzes DNS records, but to verify actual email delivery, send a test email to Red Sift Investigate. Their tool shows exactly how your emails arrive, including SPF/DKIM/DMARC pass/fail results in the headers.

DATA FRESHNESS & METHODOLOGY

All security-critical records (SPF, DMARC, DKIM, DANE/TLSA, DNSSEC, MTA-STS, TLS-RPT, BIMI, CAA) are queried live from authoritative nameservers and cross-referenced against 5 independent public DNS resolvers (Cloudflare, Google, Quad9, OpenDNS, DNS4EU) at the time of each analysis. No security verdict uses cached data.

Registrar data (RDAP) is cached for up to 24 hours because domain ownership and registration details change infrequently. Certificate Transparency logs (subdomain discovery via RFC 6962) are cached for 1 hour because CT entries are append-only historical records. Sections using cached data are marked with a CACHED badge; live queries show LIVE.

Intelligence Sources

This analysis used 4 DNS resolvers (consensus), reverse DNS (PTR), Team Cymru (ASN attribution), IANA RDAP (registrar), SecurityTrails (DNS history), crt.sh (CT logs), and SMTP probing (transport). All using open-standard protocols.

Full List
Verify Report Integrity SHA-3-512 Has this report been altered since generation? Verify below

This cryptographic hash seals the analysis data, domain, timestamp, and tool version into a tamper-evident fingerprint. Any modification to the report data will produce a different hash. This is distinct from the posture hash (used for drift detection) — the integrity hash uniquely identifies this specific report instance.

647704e542e3d88607b4db6db547c2b67d46162199c3742f3a3e675da83d8d282dcac71d7ad2f263908ffd1fadd4ba62984870ac583d97b0556f83f29066c920
Evaluations reference 12 RFCs. Methods are reproducible using the verification commands provided. Results reflect DNS state at 12 Feb 2026, 09:28 UTC.
Download Raw Intelligence Download Checksum (.sha3)

Download the intelligence dump and verify its integrity, like you would a Kali ISO or any critical artifact. The SHA-3-512 checksum covers every byte of the download — deterministic serialization ensures identical hashes across downloads.

After downloading, verify with any of these commands:

Tip: cd ~/Downloads first (or wherever you saved the files).

OpenSSL + Sidecar (macOS, Linux, WSL) 
cat dns-intelligence-nlnetlabs.nl.json.sha3 && echo '---' && openssl dgst -sha3-512 dns-intelligence-nlnetlabs.nl.json
Python 3 (cross-platform) 
python3 -c "import hashlib; print(hashlib.sha3_512(open('dns-intelligence-nlnetlabs.nl.json','rb').read()).hexdigest())"
sha3sum (coreutils 9+) 
sha3sum -a 512 dns-intelligence-nlnetlabs.nl.json
Compare the output against the .sha3 file or the checksum API at /api/analysis/632/checksum. Hash algorithm: SHA-3-512 (Keccak, NIST FIPS 202).

Every finding in this report is backed by DNS queries you can run yourself. These vetted one-liners reproduce the exact checks used to build this report for nlnetlabs.nl. Our analysis adds multi-resolver consensus, RFC-based evaluation, and cross-referencing — but the underlying data is always independently verifiable. We are intelligence analysts, not gatekeepers.

DNS Records

Query A records (IPv4) RFC 1035 
dig +noall +answer nlnetlabs.nl A
Query AAAA records (IPv6) RFC 1035 
dig +noall +answer nlnetlabs.nl AAAA
Query MX records (mail servers) RFC 1035 
dig +noall +answer nlnetlabs.nl MX
Query NS records (nameservers) RFC 1035 
dig +noall +answer nlnetlabs.nl NS
Query TXT records RFC 1035 
dig +noall +answer nlnetlabs.nl TXT

Email Authentication

Check SPF record RFC 7208 
dig +short nlnetlabs.nl TXT | grep -i spf
Check DMARC policy RFC 7489 
dig +short _dmarc.nlnetlabs.nl TXT
Check DKIM key for selector 'default' RFC 6376 
dig +short default._domainkey.nlnetlabs.nl TXT
Check DKIM key for selector 'google' RFC 6376 
dig +short google._domainkey.nlnetlabs.nl TXT

Domain Security

Check DNSSEC DNSKEY records RFC 4035 
dig +dnssec +noall +answer nlnetlabs.nl DNSKEY
Check DNSSEC DS records RFC 4035 
dig +noall +answer nlnetlabs.nl DS
Validate DNSSEC chain (requires DNSSEC-validating resolver) RFC 4035 
dig +dnssec +cd nlnetlabs.nl A @1.1.1.1

Transport Security

Check TLSA record for mxext1.mailbox.org RFC 7672 
dig +noall +answer _25._tcp.mxext1.mailbox.org TLSA
Check TLSA record for mxext2.mailbox.org RFC 7672 
dig +noall +answer _25._tcp.mxext2.mailbox.org TLSA
Check TLSA record for mxext3.mailbox.org RFC 7672 
dig +noall +answer _25._tcp.mxext3.mailbox.org TLSA
Verify TLS certificate on primary MX (mxext1.mailbox.org) RFC 6698 
openssl s_client -starttls smtp -connect mxext1.mailbox.org:25 -servername mxext1.mailbox.org 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record RFC 8461 
dig +short _mta-sts.nlnetlabs.nl TXT
Fetch MTA-STS policy file RFC 8461 
curl -sL https://mta-sts.nlnetlabs.nl/.well-known/mta-sts.txt
Check TLS-RPT record RFC 8460 
dig +short _smtp._tls.nlnetlabs.nl TXT

Brand & Trust

Check BIMI record BIMI Draft 
dig +short default._bimi.nlnetlabs.nl TXT
Check CAA records (certificate authority authorization) RFC 8659 
dig +noall +answer nlnetlabs.nl CAA

DNS Records

Check HTTPS/SVCB records RFC 9460 
dig +noall +answer nlnetlabs.nl HTTPS

Domain Security

Check CDS/CDNSKEY automation records RFC 7344 
dig +noall +answer nlnetlabs.nl CDS

Infrastructure Intelligence

RDAP domain registration lookup RFC 9083 
curl -sL 'https://rdap.org/domain/nlnetlabs.nl' | python3 -m json.tool | head -50

Transport Security

Test STARTTLS on primary MX (mxext1.mailbox.org) RFC 3207 
openssl s_client -starttls smtp -connect mxext1.mailbox.org:25 -servername mxext1.mailbox.org </dev/null 2>/dev/null | head -5

Infrastructure Intelligence

Search Certificate Transparency logs RFC 6962 
curl -s 'https://crt.sh/?q=%25.nlnetlabs.nl&output=json' | python3 -c "import json,sys; [print(e['name_value']) for e in json.load(sys.stdin)]" | sort -u | head -20
Check security.txt RFC 9116 
curl -sL https://nlnetlabs.nl/.well-known/security.txt | head -20

AI Surface

Check for llms.txt 
curl -sI https://nlnetlabs.nl/llms.txt | head -5
Check robots.txt for AI crawler rules 
curl -s https://nlnetlabs.nl/robots.txt | grep -i -E 'GPTBot|ChatGPT|Claude|Anthropic|Google-Extended|CCBot|PerplexityBot'

Infrastructure Intelligence

ASN lookup for 128.140.76.106 (Team Cymru) 
dig +short 106.76.140.128.origin.asn.cymru.com TXT
Commands use dig, openssl, and curl — standard tools available on macOS, Linux, and WSL. Results may vary slightly due to DNS propagation timing and resolver caching.
Intelligence Confidence Audit Engine Verified · 9/9 Evaluated
How confident are these results? Each protocol is independently verified against RFC standards. No self-awarded badges.
SPF
Verified 4867 runs
DKIM
Verified 4686 runs
DMARC
Verified 4851 runs
DANE/TLSA
Verified 4670 runs
DNSSEC
Verified 4848 runs
BIMI
Verified 4685 runs
MTA-STS
Verified 4688 runs
TLS-RPT
Verified 4690 runs
CAA
Verified 4682 runs
Maturity: Development → Verified → Consistent → Gold → Gold Master

Appendix: Verification Commands

The core DNS queries behind this report can be independently verified using these standard terminal commands (dig, openssl, curl). DNS Tool adds multi-resolver consensus, RFC-based evaluation, and cross-referencing on top of the raw data shown here.

DNS Records

Query A records (IPv4) (RFC 1035) 
dig +noall +answer nlnetlabs.nl A
Query AAAA records (IPv6) (RFC 1035) 
dig +noall +answer nlnetlabs.nl AAAA
Query MX records (mail servers) (RFC 1035) 
dig +noall +answer nlnetlabs.nl MX
Query NS records (nameservers) (RFC 1035) 
dig +noall +answer nlnetlabs.nl NS
Query TXT records (RFC 1035) 
dig +noall +answer nlnetlabs.nl TXT

Email Authentication

Check SPF record (RFC 7208) 
dig +short nlnetlabs.nl TXT | grep -i spf
Check DMARC policy (RFC 7489) 
dig +short _dmarc.nlnetlabs.nl TXT
Check DKIM key for selector 'default' (RFC 6376) 
dig +short default._domainkey.nlnetlabs.nl TXT
Check DKIM key for selector 'google' (RFC 6376) 
dig +short google._domainkey.nlnetlabs.nl TXT

Domain Security

Check DNSSEC DNSKEY records (RFC 4035) 
dig +dnssec +noall +answer nlnetlabs.nl DNSKEY
Check DNSSEC DS records (RFC 4035) 
dig +noall +answer nlnetlabs.nl DS
Validate DNSSEC chain (requires DNSSEC-validating resolver) (RFC 4035) 
dig +dnssec +cd nlnetlabs.nl A @1.1.1.1

Transport Security

Check TLSA record for mxext1.mailbox.org (RFC 7672) 
dig +noall +answer _25._tcp.mxext1.mailbox.org TLSA
Check TLSA record for mxext2.mailbox.org (RFC 7672) 
dig +noall +answer _25._tcp.mxext2.mailbox.org TLSA
Check TLSA record for mxext3.mailbox.org (RFC 7672) 
dig +noall +answer _25._tcp.mxext3.mailbox.org TLSA
Verify TLS certificate on primary MX (mxext1.mailbox.org) (RFC 6698) 
openssl s_client -starttls smtp -connect mxext1.mailbox.org:25 -servername mxext1.mailbox.org 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record (RFC 8461) 
dig +short _mta-sts.nlnetlabs.nl TXT
Fetch MTA-STS policy file (RFC 8461) 
curl -sL https://mta-sts.nlnetlabs.nl/.well-known/mta-sts.txt
Check TLS-RPT record (RFC 8460) 
dig +short _smtp._tls.nlnetlabs.nl TXT

Brand & Trust

Check BIMI record (BIMI Draft) 
dig +short default._bimi.nlnetlabs.nl TXT
Check CAA records (certificate authority authorization) (RFC 8659) 
dig +noall +answer nlnetlabs.nl CAA

DNS Records

Check HTTPS/SVCB records (RFC 9460) 
dig +noall +answer nlnetlabs.nl HTTPS

Domain Security

Check CDS/CDNSKEY automation records (RFC 7344) 
dig +noall +answer nlnetlabs.nl CDS

Infrastructure Intelligence

RDAP domain registration lookup (RFC 9083) 
curl -sL 'https://rdap.org/domain/nlnetlabs.nl' | python3 -m json.tool | head -50

Transport Security

Test STARTTLS on primary MX (mxext1.mailbox.org) (RFC 3207) 
openssl s_client -starttls smtp -connect mxext1.mailbox.org:25 -servername mxext1.mailbox.org </dev/null 2>/dev/null | head -5

Infrastructure Intelligence

Search Certificate Transparency logs (RFC 6962) 
curl -s 'https://crt.sh/?q=%25.nlnetlabs.nl&output=json' | python3 -c "import json,sys; [print(e['name_value']) for e in json.load(sys.stdin)]" | sort -u | head -20
Check security.txt (RFC 9116) 
curl -sL https://nlnetlabs.nl/.well-known/security.txt | head -20

AI Surface

Check for llms.txt 
curl -sI https://nlnetlabs.nl/llms.txt | head -5
Check robots.txt for AI crawler rules 
curl -s https://nlnetlabs.nl/robots.txt | grep -i -E 'GPTBot|ChatGPT|Claude|Anthropic|Google-Extended|CCBot|PerplexityBot'

Infrastructure Intelligence

ASN lookup for 128.140.76.106 (Team Cymru) 
dig +short 106.76.140.128.origin.asn.cymru.com TXT
Running Multi-Source Intelligence Audit

nlnetlabs.nl

0s
DNS records — Cloudflare, Google, Quad9, OpenDNS, DNS4EU
Email auth — SPF, DMARC, DKIM selectors
DNSSEC chain of trust & DANE/TLSA
Certificate Transparency & subdomain discovery
SMTP transport & STARTTLS verification
MTA-STS, TLS-RPT, BIMI, CAA
Registrar & infrastructure analysis
Intelligence Classification & Interpretation

Every result includes terminal commands you can run to independently verify the underlying data. No proprietary magic.