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DNS Tool
Engineer's DNS Intelligence Report
Generated 23 Feb 2026, 21:49 UTC
Duration 18.6s
Version v26.25.31
Integrity 74b84da89b2221d8da2c13c7f5edea2e96e667bff324a7254c3a6ab9b94e644dc95255bf4fbb510d4bd5e24324302f8231aacafea4674cee03a392a4818a2378
Subject Domain
nlnetlabs.nl

Engineer's DNS Intelligence Report

nlnetlabs.nl
23 Feb 2026, 21:49 UTC · 18.6s ·v26.25.31 · SHA-3-512: 74b8✱✱✱✱ Verify
Executive Methodology
Recon Mode Snapshot Re-analyze New Domain
Footprint 1 SaaS Service
DNS Security & Trust Posture
Risk Level: Medium Risk
5 protocols configured, 4 not configured Domain appears to be in deliberate DMARC monitoring phase with aggregate reporting enabled Why we go beyond letter grades
1 recommendation 1 monitoring
Intelligence Currency
Data Currency: Adequate 75/100
ICuAE Details
Currentness Excellent TTL Compliance Excellent Completeness Degraded Source Credibility Excellent TTL Relevance Degraded
DNS data shows some aging or gaps — consider re-scanning for critical decisions
Email Spoofing
Partial
Brand Impersonation
Not Setup
DNS Tampering
Protected
Certificate Control
Open
Recommended
Move DMARC policy from 'none' to 'quarantine' or 'reject'
Monitoring
DMARC record has configuration warnings — review recommended
Configured
SPF, DMARC (with warnings), DKIM, DANE, DNSSEC
Not Configured
MTA-STS, TLS-RPT, BIMI, CAA
Priority Actions 4 total Achievable posture: Low Risk
High Upgrade DMARC from p=none

Your DMARC policy is monitor-only (p=none). Upgrade to p=quarantine or p=reject after reviewing reports to actively prevent spoofing.

A quarantine or reject policy instructs receivers to take action on failing mail.
TypeTXT
Host_dmarc.nlnetlabs.nl (DMARC policy record)
Valuev=DMARC1; p=quarantine; rua=mailto:dmarc-reports@nlnetlabs.nl
RFC 7489 §6.3
Low Add CAA Records

CAA records specify which Certificate Authorities may issue certificates for your domain, reducing the risk of unauthorized certificate issuance.

CAA constrains which CAs can issue certificates for this domain.
TypeCAA
Hostnlnetlabs.nl (root of domain — adjust CA to match your provider)
Value0 issue "letsencrypt.org"
RFC 8659
Low Add TLS-RPT Reporting

Your domain has DNSSEC + DANE — the strongest email transport security available. TLS-RPT (TLS Reporting) sends you reports about TLS connection failures when other servers try to deliver mail to your domain.

TLS-RPT sends you reports about TLS connection failures to your mail servers.
TypeTXT
Host_smtp._tls.nlnetlabs.nl (SMTP TLS reporting record)
Valuev=TLSRPTv1; rua=mailto:tls-reports@nlnetlabs.nl
RFC 8460
Low Deploy MTA-STS

MTA-STS enforces TLS encryption for inbound mail delivery, preventing downgrade attacks on your mail transport.

MTA-STS tells sending servers to require TLS when delivering mail to your domain.
TypeTXT
Host_mta-sts.nlnetlabs.nl (MTA-STS policy record)
Valuev=STSv1; id=nlnetlabs.nl
RFC 8461
Registrar (RDAP) OBSERVED LIVE
Prolocation B.V. (Registrant: Benno Overeinder)
Where domain was purchased
Email Service Provider INFERRED
Self-hosted
Moderately Protected
Web Hosting
Unknown
Where website is hosted
DNS Hosting
Unknown
Where DNS records are edited
Email Security Methodology Can this domain be impersonated by email? Yes DMARC is monitor-only (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
No forensic reporting (ruf) tag — this is correct. Many tools flag the absence of ruf= as a gap. It is not. RFC 7489 §7.3 warns that forensic reports can expose PII (full message headers or bodies). Google, Microsoft, and Yahoo do not honour ruf= requests regardless. The DMARCbis draft (draft-ietf-dmarc-dmarcbis) has formally removed ruf= from the specification, confirming its deprecation. Omitting ruf= is the recommended modern practice. RFC 7489 §7.3 — Forensic Reports
Advanced cryptographic posture detected. Domain appears to be in deliberate DMARC monitoring phase with aggregate reporting enabled
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)

SPF authorizes Google Workspace servers, but MX records point to self-hosted infrastructure. The Google Workspace SPF include likely supports ancillary services (e.g., calendar invitations, shared documents) rather than primary mailbox hosting.
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 Self-hosted (inferred)
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
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 996ad31d65e03f038b8ec950f6f26611529da03e3a283e4400cba2edd04b8a88
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
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 996ad31d65e03f038b8ec950f6f26611529da03e3a283e4400cba2edd04b8a88
mxext2.mailbox.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 4758af6f02dfb5dc8795fa402e77a8a0486af5e85d2ca60c294476aadc40b220
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? Likely DMARC is monitor-only p=none (RFC 7489 §6.3) — spoofed mail is not blocked, brand faking is trivial

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

Vulnerability Disclosure Policy (security.txt) Is there a verified way to report security issues? Yes RFC 9116

security.txt properly configured

Contact

https://www.nlnetlabs.nl/security-report/

Expires

2032-11-30 Valid

Policy

https://www.nlnetlabs.nl/security-report/
PGP Signed Canonical URL
Source: https://nlnetlabs.nl/.well-known/security.txt
AI Surface Scanner Beta Is this domain discoverable by AI — and protected from abuse? No

No AI governance measures detected

llms.txt llmstxt.org
Is this domain publishing AI-readable brand context? No
No llms.txt found
No llms-full.txt found
AI Crawler Governance (robots.txt) RFC 9309 IETF Draft
Are AI crawlers explicitly allowed or blocked? Not blocked
No AI crawler blocking observed — no blocking directives found in robots.txt
Content-Usage Directive IETF Draft
Does the site express AI content-usage preferences? Not Configured
No Content-Usage directive detected. The IETF AI Preferences working group is developing a Content-Usage: directive for robots.txt that lets site owners declare whether their content may be used for AI training and inference. This is an active draft, not yet a ratified standard.
Example: Add Content-Usage: ai=no to robots.txt to deny AI training, or Content-Usage: ai=allow to explicitly permit it. Without this directive, AI crawler behavior depends on individual crawler policies and User-agent rules.
AI Recommendation Poisoning
Is this site trying to manipulate AI recommendations? No
No AI recommendation poisoning indicators found
Hidden Prompt Artifacts
Is hidden prompt-injection text present in the source? No
No hidden prompt-like artifacts detected
Evidence Log (1 item)
TypeDetailSeverityConfidence
robots_txt_no_ai_blocks robots.txt found but no AI-specific blocking directives low Observed
Public Exposure Checks Are sensitive files or secrets exposed? No

No exposed secrets detected in public page source — same-origin, non-intrusive scan of publicly visible page source and scripts.

No exposed secrets, API keys, or credentials were detected in publicly accessible page source or scripts.
Sources scanned (6)
  • https://nlnetlabs.nl/
  • https://nlnetlabs.nl/theme/js/jquery-3.2.1.min.js
  • https://nlnetlabs.nl/theme/js/bootstrap.min.js
  • https://nlnetlabs.nl/static/js/analytics.js
  • https://nlnetlabs.nl/theme/js/slick.min.js
  • https://nlnetlabs.nl/static/js/customer_carousel.js
What type of scan is this?

This is OSINT (Open Source Intelligence) collection — we check the same publicly accessible URLs that any web browser could visit. No authentication is bypassed, no ports are probed, no vulnerabilities are exploited.

Is this a PCI compliance scan? No. PCI DSS requires scans performed by an Approved Scanning Vendor (ASV) certified by the PCI Security Standards Council. DNS Tool is not an ASV. If you need PCI compliance scanning, engage a certified ASV such as Qualys, Tenable, or Trustwave.

Is this a penetration test? No. Penetration testing involves active exploitation attempts against systems with authorization. Our checks are passive observation of publicly accessible resources — the same methodology used by Shodan, Mozilla Observatory, and other OSINT platforms.

DNS Server Security Hardened

No DNS server misconfigurations found on ns.nlnetlabs.nl — Nmap NSE probes for zone transfer (AXFR), open recursion (RFC 5358), nameserver identity disclosure, and DNS cache snooping.

Check Result Detail
Zone Transfer (AXFR) Denied Zone transfer denied (correct configuration)
Open Recursion Disabled Recursion disabled (correct configuration)
Nameserver Identity Hidden No nameserver identity information disclosed
Cache Snooping Protected Cache snooping not possible (correct configuration)

Tested nameservers: ns.nlnetlabs.nl, ns5.sidn.nl, anyns.pch.net

Mail Transport Security Beta Is mail transport encrypted and verified? Yes DANE/TLSA provides cryptographic transport verification

All 3 server(s) verified: encrypted transport confirmed via direct SMTP probe and DNS policy

Policy Assessment Primary
  • DANE/TLSA records published — mail servers pin TLS certificates via DNSSEC (RFC 7672)
Telemetry
TLS-RPT not configured — domain has no visibility into TLS delivery failures from real senders
Live Probe Supplementary
MX Host STARTTLS TLS Version Cipher Certificate
mxext3.mailbox.org TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-06-10 (107 days)
Issuer: DigiCert Inc
mxext1.mailbox.org TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-06-10 (107 days)
Issuer: DigiCert Inc
mxext2.mailbox.org TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-06-10 (107 days)
Issuer: DigiCert Inc
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 Hetzner Online GmbH 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 detected via DNS TXT verification records

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? No DNSSEC signed and validated, cryptographic chain of trust verified

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

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)

Algorithm Observation: RSA/SHA-256 — MUST implement, widely deployed (RFC 8624 §3.1)
All current DNSSEC algorithms use classical cryptography. Post-quantum DNSSEC standards are in active IETF development (draft-sheth-pqc-dnssec-strategy) but no PQC algorithms have been standardized for DNSSEC yet.
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
Enterprise DNS (Mixed Configuration)
1 of 3 nameservers are dedicated (nlnetlabs.nl-branded), 2 use external provider(s). This pattern is common in large organizations using split-horizon DNS or maintaining redundancy across internal and external infrastructure.
Dedicated (organization-branded): ns.nlnetlabs.nl External provider: anyns.pch.net ns5.sidn.nl
Multi-Resolver Verification Recon: Consensus reached - 5 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

20 mxext3.mailbox.org.
10 mxext1.mailbox.org.
10 mxext2.mailbox.org.
Priority + mail server for email delivery
Self-hosted

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? 80 subdomains discovered
How did we find these?
76 unique certificates 80 current 0 expired 3 CNAMEs Source: Certificate Transparency + DNS Intelligence
Subdomains discovered via CT logs (RFC 6962), DNS probing of common service names, and CNAME chain traversal.
Certificate Authority Diversity (4 CAs observed across CT log history)
Certificate Authority Certs First Issued Last Issued Status
Let's Encrypt 65 2025-11-27 2026-02-20 Active
Google Trust Services 8 2026-01-08 2026-01-09 Active
Amazon 2 2025-01-26 2025-12-27 Active
ZeroSSL 1 2026-01-18 2026-01-18 Active
Subdomain Source Status Provider / CNAME Certificates First Seen Issuer(s)
agent.nlnetlabs.nl CT Log Current — 4 2026-02-11T11:52:24 Let's Encrypt
alpha.nlnetlabs.nl DNS Current — — — —
autodiscover.nlnetlabs.nl DNS Current mailbox.org — — —
aws.manson.nlnetlabs.nl CT Log Current vultr.manson.nlnetlabs.nl 4 2026-02-07T00:16:34 Let's Encrypt
bartok.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
bela.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
blog.nlnetlabs.nl CT Log Current nlnetlabs.ghost.io 2 2026-01-18T00:00:00 ZeroSSL
blogs.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
cascade.docs.nlnetlabs.nl CT Log Current readthedocs.io 4 2025-12-28T14:34:27 Let's Encrypt
cascade.nlnetlabs.nl CT Log Current — 2 2026-01-22T09:58:57 Let's Encrypt
community.nlnetlabs.nl CT Log Current nlnetlabs.discoursehosting.net 2 2026-01-23T08:50:17 Let's Encrypt
conference.nlnetlabs.nl DNS Current open.nlnetlabs.nl — — —
dicht.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
dnst.docs.nlnetlabs.nl CT Log Current — 4 2025-12-29T15:25:15 Let's Encrypt
dnsthought.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:15:21 Let's Encrypt
eder.nlnetlabs.nl CT Log Current — 4 2026-02-04T00:15:13 Let's Encrypt
email.ghost.blog.nlnetlabs.nl CT Log Current — 2 2026-01-08T09:31:56 Let's Encrypt
getdns.nlnetlabs.nl CT Log Current — 4 2026-02-04T00:16:20 Let's Encrypt
gogs.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
ieniemienie.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
igor.nlnetlabs.nl CT Log Current — 2 2026-01-23T14:35:51 Let's Encrypt
imap.nlnetlabs.nl CT Log Current open.nlnetlabs.nl 4 2026-02-02T00:22:33 Let's Encrypt
insecure.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:14:59 Let's Encrypt
jabber.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
kimai.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
krill.docs.nlnetlabs.nl CT Log Current readthedocs.io 3 2026-01-08T15:24:40 Google Trust Services
krill.nlnetlabs.nl CT Log Current — 2 2026-01-21T11:24:29 Let's Encrypt
lists.nlnetlabs.nl CT Log Current — 4 2026-02-06T00:17:36 Let's Encrypt
mailman.nlnetlabs.nl CT Log Current — 4 2026-02-06T00:17:36 Let's Encrypt
manson.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:16:34 Let's Encrypt
metriculator.nlnetlabs.nl CT Log Current — 4 2026-01-25T04:15:29 Let's Encrypt
monitoring-agent.nlnetlabs.nl CT Log Current — 4 2026-02-11T11:52:24 Let's Encrypt
mox.nlnetlabs.nl CT Log Current — 4 2026-02-04T00:14:48 Let's Encrypt
mysql.nlnetlabs.nl DNS Current open.nlnetlabs.nl — — —
nagios.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
nate.nlnetlabs.nl CT Log Current — 2 2025-12-27T11:20:21 Let's Encrypt
nlnet.is.not.nlnetlabs.nl CT Log Current — 4 2026-01-26T11:27:46 Let's Encrypt
nlnetlabs.blogs.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
nlnetlabs4fastly.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
ns.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
ns1.nlnetlabs.nl DNS Current — — — —
ns3.nlnetlabs.nl CT Log Current — 2 2026-02-12T13:05:42 Let's Encrypt
ns4.nlnetlabs.nl DNS Current — — — —
nsd.docs.nlnetlabs.nl CT Log Current readthedocs.io 8 2026-02-15T09:21:26 Let's Encrypt
office.nlnetlabs.nl DNS Current — — — —
ohno.nlnetlabs.nl CT Log Current metriculator.nlnetlabs.nl 2 2025-12-31T11:00:20 Let's Encrypt
open.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
overview.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
packages.nlnetlabs.nl CT Log Current d3gyelix7lpwbo.cloudfront.net 8 2025-12-27T00:00:00 Amazon
pino.nlnetlabs.nl CT Log Current — 4 2026-02-03T00:30:40 Let's Encrypt
redmine.nlnetlabs.nl CT Log Current bela.nlnetlabs.nl 4 2026-02-02T00:22:33 Let's Encrypt
report.nlnetlabs.nl DNS Current — — — —
resolver.nlnetlabs.nl CT Log Current — 4 2026-02-19T04:31:54 Let's Encrypt
roto.docs.nlnetlabs.nl CT Log Current readthedocs.io 8 2026-02-06T09:34:07 Let's Encrypt
rotonda.docs.nlnetlabs.nl CT Log Current readthedocs.io 4 2026-01-16T00:12:39 Let's Encrypt
routinator.docs.nlnetlabs.nl CT Log Current — 3 2026-01-09T05:08:32 Google Trust Services
routinator.nlnetlabs.nl CT Log Current — 2 2025-12-27T11:24:25 Let's Encrypt
rpkitest.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:16:34 Let's Encrypt
rpkitest4.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:16:34 Let's Encrypt
rpkitest6.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:16:34 Let's Encrypt
rrdp.krill.nlnetlabs.nl CT Log Current krill.nlnetlabs.nl 2 2026-01-21T11:24:29 Let's Encrypt
rt.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
rt4.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
rtrtr.docs.nlnetlabs.nl CT Log Current — 3 2026-01-09T03:05:18 Google Trust Services
simdzone.docs.nlnetlabs.nl CT Log Current readthedocs.io 8 2026-02-12T04:18:55 Let's Encrypt
simplomon.nlnetlabs.nl CT Log Current metriculator.nlnetlabs.nl 2 2026-01-02T00:05:14 Let's Encrypt
smtp.nlnetlabs.nl CT Log Current open.nlnetlabs.nl 4 2026-02-02T00:22:33 Let's Encrypt
social.nlnetlabs.nl CT Log Current vip.masto.host 4 2026-02-12T05:16:47 Let's Encrypt
ster.nlnetlabs.nl CT Log Current igor.nlnetlabs.nl 8 2026-02-06T04:17:46 Let's Encrypt
tilde.nlnetlabs.nl CT Log Current — 4 2026-02-15T11:21:43 Let's Encrypt
tutorial.nlnetlabs.nl CT Log Current — 2 2026-02-07T19:18:23 Let's Encrypt
twentyfive.nlnetlabs.nl CT Log Current igor.nlnetlabs.nl 4 2026-02-20T01:07:32 Let's Encrypt
unbound.docs.nlnetlabs.nl CT Log Current readthedocs.io 3 2026-01-09T16:31:45 Google Trust Services
unbound.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
uren.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
usg.nlnetlabs.nl CT Log Current — 4 2026-02-04T00:15:01 Let's Encrypt
www.dnsthought.nlnetlabs.nl CT Log Current bill.nlnetlabs.nl 4 2026-02-07T00:15:21 Let's Encrypt
www.insecure.nlnetlabs.nl CT Log Current — 4 2026-02-07T00:14:59 Let's Encrypt
www.nlnetlabs.nl CT Log Current — 6 2026-02-02T00:22:33 Let's Encrypt
xmpp.nlnetlabs.nl CT Log Current — 4 2026-02-02T00:22:33 Let's Encrypt
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
20 mxext3.mailbox.org.
10 mxext1.mailbox.org.
10 mxext1.mailbox.org.
10 mxext2.mailbox.org.
10 mxext2.mailbox.org.
20 mxext3.mailbox.org.
NS RFC 1035 Synchronized 3 / 3 records
ns.nlnetlabs.nl.
ns.nlnetlabs.nl.
ns5.sidn.nl.
ns5.sidn.nl.
anyns.pch.net.
anyns.pch.net.
SOA RFC 1035 Synchronized 1 / 1 records
ns.nlnetlabs.nl. hostmaster.nlnetlabs.nl. 2026021600 28800 7200 604800 240
ns.nlnetlabs.nl. hostmaster.nlnetlabs.nl. 2026021600 28800 7200 604800 240
TXT RFC 7208 §4 Synchronized 3 / 3 records
1password-site-verification=QAXPQAT46NGABHYNFZ5HGZUELQ
Stichting NLnet Labs zone
v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
1password-site-verification=QAXPQAT46NGABHYNFZ5HGZUELQ
Stichting NLnet Labs zone
v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
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), 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.

74b84da89b2221d8da2c13c7f5edea2e96e667bff324a7254c3a6ab9b94e644dc95255bf4fbb510d4bd5e24324302f8231aacafea4674cee03a392a4818a2378
Evaluations reference 12 RFCs. Methods are reproducible using the verification commands provided. Results reflect DNS state at 23 Feb 2026, 21:49 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/3997/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 mxext3.mailbox.org RFC 7672 
dig +noall +answer _25._tcp.mxext3.mailbox.org TLSA
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
Verify TLS certificate on primary MX (mxext3.mailbox.org) RFC 6698 
openssl s_client -starttls smtp -connect mxext3.mailbox.org:25 -servername mxext3.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 (mxext3.mailbox.org) RFC 3207 
openssl s_client -starttls smtp -connect mxext3.mailbox.org:25 -servername mxext3.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 4874 runs
DKIM
Verified 4692 runs
DMARC
Verified 4857 runs
DANE/TLSA
Verified 4676 runs
DNSSEC
Verified 4855 runs
BIMI
Verified 4691 runs
MTA-STS
Verified 4694 runs
TLS-RPT
Verified 4696 runs
CAA
Verified 4688 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 mxext3.mailbox.org (RFC 7672) 
dig +noall +answer _25._tcp.mxext3.mailbox.org TLSA
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
Verify TLS certificate on primary MX (mxext3.mailbox.org) (RFC 6698) 
openssl s_client -starttls smtp -connect mxext3.mailbox.org:25 -servername mxext3.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 (mxext3.mailbox.org) (RFC 3207) 
openssl s_client -starttls smtp -connect mxext3.mailbox.org:25 -servername mxext3.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.