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DNS Tool
Engineer's DNS Intelligence Report
Generated 18 Feb 2026, 12:33 UTC
Duration 5.8s
Version v26.20.48
Integrity 5756ebcbfec1a3852bc6262ef5a0e98c38ce3b9d6b3c95a8854756f7d97f0c7c6dc354e4f2b4fc771c708e9d4df1d457f0b5614c26dee86164447e861e2b6078
Subject Domain
isc.org

Engineer's DNS Intelligence Report

isc.org
18 Feb 2026, 12:33 UTC · 5.8s ·v26.20.48 · SHA-3-512: 5756✱✱✱✱ Verify
Executive Methodology
Recon Mode Snapshot Re-analyze New Domain
Footprint 2 SaaS Services
DNS Security & Trust Posture
Risk Level: Medium Risk
7 protocols configured, 2 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
Suggested Scanner Configuration High Confidence
Based on 17 historical scans of this domain
Parameter Current Suggested Severity Rationale
timeout_seconds 5s 8s low Average scan duration is 44.0s, suggesting DNS responses are slow for this domain. Increasing timeout from 5s to 8s prevents premature resolution failures.
RFC 8767
Suggestions require explicit approval before applying. No automatic changes will be made.
Email Spoofing
Partial
Brand Impersonation
Not Setup
DNS Tampering
Protected
Certificate Control
Configured
Recommended
Move DMARC policy from 'none' to 'quarantine' or 'reject'
Monitoring
DMARC record has configuration warnings — review recommended
Configured
SPF, DMARC (with warnings), DKIM, TLS-RPT, DANE, DNSSEC, CAA
Not Configured
MTA-STS, BIMI
Priority Actions 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.isc.org (DMARC policy record)
Valuev=DMARC1; p=quarantine; rua=mailto:dmarc-reports@isc.org
RFC 7489 §6.3
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.isc.org (MTA-STS policy record)
Valuev=STSv1; id=isc.org
RFC 8461
Registrar (RDAP) OBSERVED LIVE
Tucows Domains Inc.
Where domain was purchased
Email Service Provider
Unknown
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 7/10 lookups

SPF valid with industry-standard soft fail (~all), 7/10 lookups

v=spf1 a mx ip4:149.20.0.0/20 ip6:2001:04F8::0/32 ip6:2001:500:60::65/128 ip4:199.6.1.0/24 ip6:2001:500:6b:2::0/64 include:shops.shopify.com include:servers.mcsv.net include:_spf.salesforce.com include:spf-a.customercenter.net include:spf-b.customercenter.net include:spf-c.customercenter.net ~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=reject; rua=mailto:0rzssdyk@ag.dmarcian.com; ruf=mailto:0rzssdyk@fr.dmarcian.com, mailto:dmarcforensic@isc.org; fo=1;
Policy p=none provides no protection - spoofed emails reach inboxes
Forensic reporting (ruf) is configured, but most major providers do not send forensic reports. 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. The DMARCbis draft (draft-ietf-dmarc-dmarcbis) has formally removed ruf= from the specification. Consider removing this tag to simplify your record. 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 3 selector(s)

k2._domainkey
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAv2aC2KjGKLOwTweBY5A9RpjsxaBXR9r7OAU6U8/zn92ivImI75naUujWbItRI/QmL1jy5PWGqLwoUA0b90ObWaLDc+i9MtTNmGeWO009hr20fIxhGg6XBT2kjZ1DTThopSe1nAndsupmcBwlQ5Q6LJ+ZAxLcujnPIxM0ZBLmgpkv8u6RfY4eFP8OLvdAW3oSuB0DyLDigQX4Sj8wBO4YIdQH6AAmBeOsidsKAFNFUCpc3vCxtBDR12U+cBg724l3sBkMQ8evnz6idnqxq9QAVYh8k4kJ+RP+6cqTdy7LjIm8xY/bQNpQIpGUAuDo2DjLcCDun9DAI4Q/3z+Q0o9QuQIDAQAB;
zendesk1._domainkey Zendesk
v=DKIM1;t=s;n=core;k=rsa;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA9IqdLrO3Zr2/56MHt8oQVCQorP0Bl2Fz9sM2tFBnJCdB/HogQmuudEg2xAovCN2PYpw44UijIvPuBoT9vxiv6ZCBJTLJXa82r6ke5rE4tbe9NKFIrVIb9S306cJDrnKFMDb8p0dU/Su0+eUR5gVAOtCuz2L8HAzs5edvsEvD/Fb4ny1RLNSEPZkIQLfGhVxQeWANm3+1Jwb/OBVXV9k0nKpWrpgqcmO7NzroJirp014RQY7rGi60JLUubc6XhvoFQBQrtOAdVlZC5wvfS1bgpq5kQpdP7cajIqWCeqxPTeo0ZUpey2ZcaygEsZz0Z3Gs5wDzyuqd7/ADpr2jNF7ozwIDAQAB
zendesk2._domainkey Zendesk
v=DKIM1; t=s; n=core; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmiSFNkgXrO3I8aOaPONDZWHv027rkiGIwb838OyXPgvFDEkCV/qGcdXSjZnaVAadrTm/oKnL8WOltP9zB1FLEuKt0fTi5zRyKPE4oIYCnEzXwrGqzjUcCABQBawQVqvXjDOaYh9Lhp8W5PYOLo905vRW7ipyIMDhuzBOJls91/WWXnNK0OwP3RghiisZjA3K2KqtRwf7w6GjNeNuAMNhvcmgAN15d/mhK+dev/hcRbal66RoYyTD8c0F0isahWH0envEX8aj+SBhheNk0/U37dGE+4nFaY5yP9CUlYjFKDSIKZgHzG4Hci3t/RubU58pi6BCrQQdAFvIOeDFeCZ0ywIDAQAB
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? Yes — reports configured
Success

TLS-RPT configured - receiving TLS delivery reports

v=TLSRPTv1; rua=mailto:0rzssdyk@tls.us.dmarcian.com

DMARC External Reporting Authorization RFC 7489 §7.1

Are external report receivers authorized? Yes — all authorized
Success

All 2 external reporting domains properly authorized

External Domain Authorization Auth Record
ag.dmarcian.com Authorized v=DMARC1;
fr.dmarcian.com Authorized v=DMARC1;
DANE / TLSA Verified Recon Methodology Can mail servers establish identity without a public CA? Yes
RFC 7672 §3 RFC 6698 §2 2/2 MX

DANE configured — TLSA records found for all 2 MX hosts

MX Host Usage Selector Match Certificate Data
mx.pao1.isc.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 865c0bc73ec3dac90f73b3d1cf6ba08ecb2848134aab479b6279fe7044a0fa89
mx.ams1.isc.org 3 DANE-EE (Domain-issued certificate) Public key only (SubjectPublicKeyInfo) SHA-256 40f9c00cff49771c74615e4b366ec19e110928396904539b97878b6e6811bfe1
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) — spoofed mail is not blocked

BIMI BIMI Spec Verified Warning

Is the brand identity verified and displayed in inboxes? No

No BIMI record found

CAA RFC 8659 §4 Verified Success IODEF

Does this domain restrict who can issue TLS certificates? Yes

CAA configured - only certainly.com, DigiCert, Sectigo, Let's Encrypt, GlobalSign, pki.goog can issue certificates (wildcard issuance: trust-provider.com, usertrust.com, Sectigo, GlobalSign, certainly.com per RFC 8659 §4.3)

Authorized CAs: certainly.com DigiCert Sectigo Let's Encrypt GlobalSign pki.goog
0 issue "certainly.com"
0 issue "Digicert.com"
0 issuewild "trust-provider.com"
0 issuewild "usertrust.com"
0 issue "comodoca.com"
0 issuewild "comodoca.com"
0 issuewild "sectigo.com"
0 issuewild "globalsign.com"
0 issue "letsencrypt.org"
0 issue "sectigo.com"
0 issue "globalsign.com"
0 iodef "mailto:hostmaster@isc.org"
0 issue "pki.goog"
0 issuewild "certainly.com"
Since September 2025, all public CAs must verify domain control from multiple geographic locations (Multi-Perspective Issuance Corroboration, CA/B Forum Ballot SC-067). CAA records are now checked from multiple network perspectives before certificate issuance.
Vulnerability Disclosure Policy (security.txt) Is there a verified way to report security issues? No RFC 9116

No security.txt found

A security.txt file at /.well-known/security.txt provides security researchers with a standardized way to report vulnerabilities. See securitytxt.org for a generator.
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.
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.

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

Transport encryption enforced via DNS policy (2 signal(s))

Policy Assessment Primary
  • DANE/TLSA records published — mail servers pin TLS certificates via DNSSEC (RFC 7672)
  • TLS-RPT configured — domain monitors TLS delivery failures (RFC 8460)
Telemetry
TLS-RPT configured — domain receives reports about TLS delivery failures from sending mail servers (RFC 8460)
Reporting to: mailto:0rzssdyk@tls.us.dmarcian.com
Live Probe Supplementary
Skipped — SMTP probe skipped — outbound TCP port 25 is blocked by cloud hosting provider. This is standard for all major cloud platforms (AWS, GCP, Azure, Replit) as an anti-spam measure. Transport security is assessed via DNS policy records above, which is the standards-aligned primary method per NIST SP 800-177 Rev. 1.
Infrastructure Intelligence Who hosts this domain and what services power it? Direct

ASN / Network Success

Resolved 1 unique ASN(s) across 8 IP address(es)

ASNNameCountry
AS54113 Fastly, Inc. US
IPv4 Mappings:
151.101.194.217 → AS54113 (151.101.192.0/22)
151.101.2.217 → AS54113 (151.101.0.0/22)
151.101.66.217 → AS54113 (151.101.64.0/22)
151.101.130.217 → AS54113 (151.101.128.0/22)
IPv6 Mappings:
2a04:4e42:600::729 → AS54113 (2a04:4e42:600::/48)
2a04:4e42:400::729 → AS54113 (2a04:4e42:400::/48)
2a04:4e42::729 → AS54113 (2a04:4e42::/48)
2a04:4e42:200::729 → AS54113 (2a04:4e42:200::/48)

Edge / CDN Success

Domain appears to use direct origin hosting

SaaS TXT Footprint Success 2 services

2 SaaS services 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
Google Workspace google-site-verification=grXE1SbXWNed6C5yQgI8fwxgucE0DppnbICbhZr9qG0
Microsoft 365 MS=2583E0E0DCCBF33EC6DAFF0B4BFBAF78FFCF7AD0
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 ECDSA P-256/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):
7250 13 2 A30B3F78B6DDE9A4A9A2AD0C805518B4F49EC62E7D3F4531D33DE697CDA01CB2

NS Delegation Verified

5 nameserver(s) configured

Nameservers: ns.isc.afilias-nst.info ns1.isc.org ns2.isc.org ns3.isc.org nsp.dnsnode.net
Multi-Resolver Verification Recon: Discrepancy detected - Some resolvers returned different results (1 difference found)
Resolver Differences:
TXT: OpenDNS returned different results: [F8C4EB9011 MS=2583E0E0DCCBF33EC6DAFF0B4BFBAF78FFCF7AD0 _globalsign-domain-verification=ckxXdoIq27XGYE4ATbBYQOBeV7PTJWRxYe-PXDyzMX google-site-verification=6v652rgkk_kI6Ky32iGdxqXjQ4_BAd5DYKsrnRXKUiE google-site-verification=grXE1SbXWNed6C5yQgI8fwxgucE0DppnbICbhZr9qG0 google-site-verification=wg4m8dWi3XVPRYmtBoy6xSKp3juhxIWa6UdxjZkNQCg]
This may indicate DNS propagation in progress or geo-based DNS routing.

CDS / CDNSKEY (DNSSEC Automation) RFC 7344 Success CDS CDNSKEY

Full RFC 8078 automated DNSSEC key rollover signaling detected (CDS + CDNSKEY)

Key TagAlgorithmDigest TypeDigest
7250 ECDSAP256SHA256 2
CDNSKEY Records:
FlagsProtocolAlgorithmPublic Key
257 3 ECDSAP256SHA256
Traffic & Routing Where does this domain's traffic actually terminate?

AIPv4 Address

151.101.194.217
151.101.2.217
151.101.66.217
151.101.130.217
Where the domain points for web traffic

AAAAIPv6 Address

2a04:4e42:600::729
2a04:4e42:400::729
2a04:4e42::729
2a04:4e42:200::729
IPv6 ready

MXMail Servers

5 mx.pao1.isc.org.
10 mx.ams1.isc.org.
Priority + mail server for email delivery

SRVServices

No SRV records
No service-specific routing configured
Web: Reachable (4 IPv4, 4 IPv6) Mail: 2 servers Services: None
Subdomain Discovery RFC 6962 Recon LIVE What subdomains and infrastructure are exposed in certificate logs? 19 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
CT logs unavailable 19 current 0 expired 8 CNAMEs Source: Certificate Transparency + DNS Intelligence
Subdomains discovered via CT logs (RFC 6962), DNS probing of common service names, and CNAME chain traversal.
Subdomain Source Status Provider / CNAME Certificates First Seen Issuer(s)
docs.isc.org DNS Current — — — —
ftp.isc.org DNS Current ftp2.isc.org — — —
gitlab.isc.org DNS Current — — — —
jenkins.isc.org DNS Current web.isc.org — — —
kb.isc.org DNS Current lb-cdmz1.document360.io — — —
monitor.isc.org DNS Current crowsnest-oak1.isc.org — — —
nagios.isc.org DNS Current crowsnest-oak1.isc.org — — —
ns1.isc.org DNS Current — — — —
ns2.isc.org DNS Current — — — —
ns3.isc.org DNS Current — — — —
repo.isc.org DNS Current — — — —
shop.isc.org DNS Current shops.myshopify.com — — —
sso.isc.org DNS Current — — — —
support.isc.org DNS Current — — — —
vpn.isc.org DNS Current — — — —
web.isc.org DNS Current — — — —
wiki.isc.org DNS Current — — — —
www.isc.org DNS Current isc.map.fastlydns.net — — —
www2.isc.org DNS Current dualstack.osff2.map.fastly.net — — —
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 4 / 4 records
151.101.194.217
151.101.66.217
151.101.2.217
151.101.130.217
151.101.66.217
151.101.194.217
151.101.130.217
151.101.2.217
AAAA Synchronized 4 / 4 records
2a04:4e42:600::729
2a04:4e42::729
2a04:4e42:400::729
2a04:4e42:200::729
2a04:4e42::729
2a04:4e42:400::729
2a04:4e42:200::729
2a04:4e42:600::729
CAA RFC 8659 §4 Synchronized 14 / 14 records
0 issue "sectigo.com"
0 issue "certainly.com"
0 issuewild "trust-provider.com"
0 issue "comodoca.com"
0 issuewild "comodoca.com"
0 issue "globalsign.com"
0 issuewild "globalsign.com"
0 issue "letsencrypt.org"
0 issuewild "certainly.com"
0 issue "pki.goog"
0 issue "letsencrypt.org"
0 issue "sectigo.com"
0 issue "certainly.com"
0 issuewild "certainly.com"
0 issue "pki.goog"
0 issuewild "comodoca.com"
0 issue "comodoca.com"
0 issuewild "globalsign.com"
0 issuewild "sectigo.com"
0 issuewild "sectigo.com"
0 issuewild "usertrust.com"
0 issuewild "trust-provider.com"
0 iodef "mailto:hostmaster@isc.org"
0 issuewild "usertrust.com"
0 issue "globalsign.com"
0 iodef "mailto:hostmaster@isc.org"
0 issue "Digicert.com"
0 issue "Digicert.com"
DMARC _dmarc.isc.org RFC 7489 §6.3 Synchronized 1 / 1 records
v=DMARC1; p=none; sp=reject; rua=mailto:0rzssdyk@ag.dmarcian.com; ruf=mailto:0rzssdyk@fr.dmarcian.com, mailto:dmarcforensic@isc.org; fo=1;
v=DMARC1; p=none; sp=reject; rua=mailto:0rzssdyk@ag.dmarcian.com; ruf=mailto:0rzssdyk@fr.dmarcian.com, mailto:dmarcforensic@isc.org; fo=1;
MX RFC 5321 Synchronized 2 / 2 records
5 mx.pao1.isc.org.
10 mx.ams1.isc.org.
10 mx.ams1.isc.org.
5 mx.pao1.isc.org.
NS RFC 1035 Synchronized 5 / 5 records
ns.isc.afilias-nst.info.
nsp.dnsnode.net.
ns2.isc.org.
ns.isc.afilias-nst.info.
ns3.isc.org.
ns1.isc.org.
nsp.dnsnode.net.
ns2.isc.org.
ns1.isc.org.
ns3.isc.org.
SOA RFC 1035 Synchronized 1 / 1 records
ns-int.isc.org. hostmaster.isc.org. 2026020577 7200 3600 24796800 3600
ns-int.isc.org. hostmaster.isc.org. 2026020577 7200 3600 24796800 3600
TLS-RPT _smtp._tls.isc.org RFC 8460 §3 Synchronized 1 / 1 records
v=TLSRPTv1; rua=mailto:0rzssdyk@tls.us.dmarcian.com
v=TLSRPTv1; rua=mailto:0rzssdyk@tls.us.dmarcian.com
TXT RFC 7208 §4 7 / 0 records
v=spf1 a mx ip4:149.20.0.0/20 ip6:2001:04F8::0/32 ip6:2001:500:60::65/128 ip4:199.6.1.0/24 ip6:2001:500:6b:2::0/64 include:shops.shopify.com include:servers.mcsv.net include:_spf.salesforce.com include:spf-a.customercenter.net include:spf-b.customercenter.net include:spf-c.customercenter.net ~all
—
google-site-verification=grXE1SbXWNed6C5yQgI8fwxgucE0DppnbICbhZr9qG0
—
google-site-verification=wg4m8dWi3XVPRYmtBoy6xSKp3juhxIWa6UdxjZkNQCg
—
F8C4EB9011
—
_globalsign-domain-verification=ckxXdoIq27XGYE4ATbBYQOBeV7PTJWRxYe-PXDyzMX
—
google-site-verification=6v652rgkk_kI6Ky32iGdxqXjQ4_BAd5DYKsrnRXKUiE
—
MS=2583E0E0DCCBF33EC6DAFF0B4BFBAF78FFCF7AD0
—
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.

5756ebcbfec1a3852bc6262ef5a0e98c38ce3b9d6b3c95a8854756f7d97f0c7c6dc354e4f2b4fc771c708e9d4df1d457f0b5614c26dee86164447e861e2b6078
Evaluations reference 12 RFCs. Methods are reproducible using the verification commands provided. Results reflect DNS state at 18 Feb 2026, 12:33 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-isc.org.json.sha3 && echo '---' && openssl dgst -sha3-512 dns-intelligence-isc.org.json
Python 3 (cross-platform) 
python3 -c "import hashlib; print(hashlib.sha3_512(open('dns-intelligence-isc.org.json','rb').read()).hexdigest())"
sha3sum (coreutils 9+) 
sha3sum -a 512 dns-intelligence-isc.org.json
Compare the output against the .sha3 file or the checksum API at /api/analysis/2117/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 isc.org. 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 isc.org A
Query AAAA records (IPv6) RFC 1035 
dig +noall +answer isc.org AAAA
Query MX records (mail servers) RFC 1035 
dig +noall +answer isc.org MX
Query NS records (nameservers) RFC 1035 
dig +noall +answer isc.org NS
Query TXT records RFC 1035 
dig +noall +answer isc.org TXT

Email Authentication

Check SPF record RFC 7208 
dig +short isc.org TXT | grep -i spf
Check DMARC policy RFC 7489 
dig +short _dmarc.isc.org TXT
Check DKIM key for selector 'k2' RFC 6376 
dig +short k2._domainkey.isc.org TXT
Check DKIM key for selector 'zendesk1' RFC 6376 
dig +short zendesk1._domainkey.isc.org TXT
Check DKIM key for selector 'zendesk2' RFC 6376 
dig +short zendesk2._domainkey.isc.org TXT

Domain Security

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

Transport Security

Check TLSA record for mx.pao1.isc.org RFC 7672 
dig +noall +answer _25._tcp.mx.pao1.isc.org TLSA
Check TLSA record for mx.ams1.isc.org RFC 7672 
dig +noall +answer _25._tcp.mx.ams1.isc.org TLSA
Verify TLS certificate on primary MX (mx.pao1.isc.org) RFC 6698 
openssl s_client -starttls smtp -connect mx.pao1.isc.org:25 -servername mx.pao1.isc.org 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record RFC 8461 
dig +short _mta-sts.isc.org TXT
Fetch MTA-STS policy file RFC 8461 
curl -sL https://mta-sts.isc.org/.well-known/mta-sts.txt
Check TLS-RPT record RFC 8460 
dig +short _smtp._tls.isc.org TXT

Brand & Trust

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

DNS Records

Check HTTPS/SVCB records RFC 9460 
dig +noall +answer isc.org HTTPS

Domain Security

Check CDS/CDNSKEY automation records RFC 7344 
dig +noall +answer isc.org CDS

Infrastructure Intelligence

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

Transport Security

Test STARTTLS on primary MX (mx.pao1.isc.org) RFC 3207 
openssl s_client -starttls smtp -connect mx.pao1.isc.org:25 -servername mx.pao1.isc.org </dev/null 2>/dev/null | head -5

Infrastructure Intelligence

Search Certificate Transparency logs RFC 6962 
curl -s 'https://crt.sh/?q=%25.isc.org&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://isc.org/.well-known/security.txt | head -20

AI Surface

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

Infrastructure Intelligence

ASN lookup for 151.101.194.217 (Team Cymru) 
dig +short 217.194.101.151.origin.asn.cymru.com TXT
ASN lookup for 151.101.2.217 (Team Cymru) 
dig +short 217.2.101.151.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 4898 runs
DKIM
Verified 4716 runs
DMARC
Verified 4881 runs
DANE/TLSA
Verified 4700 runs
DNSSEC
Verified 4879 runs
BIMI
Verified 4715 runs
MTA-STS
Verified 4718 runs
TLS-RPT
Verified 4720 runs
CAA
Verified 4712 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 isc.org A
Query AAAA records (IPv6) (RFC 1035) 
dig +noall +answer isc.org AAAA
Query MX records (mail servers) (RFC 1035) 
dig +noall +answer isc.org MX
Query NS records (nameservers) (RFC 1035) 
dig +noall +answer isc.org NS
Query TXT records (RFC 1035) 
dig +noall +answer isc.org TXT

Email Authentication

Check SPF record (RFC 7208) 
dig +short isc.org TXT | grep -i spf
Check DMARC policy (RFC 7489) 
dig +short _dmarc.isc.org TXT
Check DKIM key for selector 'k2' (RFC 6376) 
dig +short k2._domainkey.isc.org TXT
Check DKIM key for selector 'zendesk1' (RFC 6376) 
dig +short zendesk1._domainkey.isc.org TXT
Check DKIM key for selector 'zendesk2' (RFC 6376) 
dig +short zendesk2._domainkey.isc.org TXT

Domain Security

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

Transport Security

Check TLSA record for mx.pao1.isc.org (RFC 7672) 
dig +noall +answer _25._tcp.mx.pao1.isc.org TLSA
Check TLSA record for mx.ams1.isc.org (RFC 7672) 
dig +noall +answer _25._tcp.mx.ams1.isc.org TLSA
Verify TLS certificate on primary MX (mx.pao1.isc.org) (RFC 6698) 
openssl s_client -starttls smtp -connect mx.pao1.isc.org:25 -servername mx.pao1.isc.org 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record (RFC 8461) 
dig +short _mta-sts.isc.org TXT
Fetch MTA-STS policy file (RFC 8461) 
curl -sL https://mta-sts.isc.org/.well-known/mta-sts.txt
Check TLS-RPT record (RFC 8460) 
dig +short _smtp._tls.isc.org TXT

Brand & Trust

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

DNS Records

Check HTTPS/SVCB records (RFC 9460) 
dig +noall +answer isc.org HTTPS

Domain Security

Check CDS/CDNSKEY automation records (RFC 7344) 
dig +noall +answer isc.org CDS

Infrastructure Intelligence

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

Transport Security

Test STARTTLS on primary MX (mx.pao1.isc.org) (RFC 3207) 
openssl s_client -starttls smtp -connect mx.pao1.isc.org:25 -servername mx.pao1.isc.org </dev/null 2>/dev/null | head -5

Infrastructure Intelligence

Search Certificate Transparency logs (RFC 6962) 
curl -s 'https://crt.sh/?q=%25.isc.org&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://isc.org/.well-known/security.txt | head -20

AI Surface

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

Infrastructure Intelligence

ASN lookup for 151.101.194.217 (Team Cymru) 
dig +short 217.194.101.151.origin.asn.cymru.com TXT
ASN lookup for 151.101.2.217 (Team Cymru) 
dig +short 217.2.101.151.origin.asn.cymru.com TXT
Running Multi-Source Intelligence Audit

isc.org

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.