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DNS Tool
Engineer's DNS Intelligence Report
Generated 22 Feb 2026, 04:20 UTC
Duration 35.6s
Version v26.23.53
Integrity ce8aa57b9cd09c85fdd625fa86dce896fd34557b55a229ce23f1414d21c397a62c87bc1d94561983cc90e1a9151063c2d482c52ca589d3d1c3367b283f5f0f47
Subject Domain
github.com

Engineer's DNS Intelligence Report

github.com
22 Feb 2026, 04:20 UTC · 35.6s ·v26.23.53 · SHA-3-512: ce8a✱✱✱✱ Verify
Executive Methodology
Recon Mode Snapshot Re-analyze New Domain
Footprint Google Workspace 10 SaaS Services
DNS Security & Trust Posture
Risk Level: Low Risk
4 protocols configured, 4 not configured, 1 unavailable on provider Why we go beyond letter grades
Suggested Scanner Configuration High Confidence
Based on 20 historical scans of this domain
Parameter Current Suggested Severity Rationale
timeout_seconds 5s 8s low Average scan duration is 31.9s, 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
Protected
Brand Impersonation
Not Setup
DNS Tampering
Unsigned
Certificate Control
Configured
Configured
SPF, DMARC (reject), DKIM, CAA
Not Configured
MTA-STS, TLS-RPT, BIMI, DNSSEC
Unavailable on Provider
DANE
Priority Actions 4 total Achievable posture: Secure
Medium Enable DNSSEC

DNSSEC is not enabled for this domain. DNSSEC provides cryptographic authentication of DNS responses, preventing cache poisoning and DNS spoofing attacks.

RFC 4035
Low Add BIMI Record

Your domain has DMARC reject — you qualify for BIMI, which displays your brand logo in receiving email clients that support it (Gmail, Apple Mail, Yahoo).

BIMI displays your verified brand logo next to your emails in supporting mail clients.
TypeTXT
Hostdefault._bimi.github.com (BIMI default record)
Valuev=BIMI1; l=https://github.com/brand/logo.svg
RFC 9495
Low Add TLS-RPT Reporting

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.github.com (SMTP TLS reporting record)
Valuev=TLSRPTv1; rua=mailto:tls-reports@github.com
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.github.com (MTA-STS policy record)
Valuev=STSv1; id=github.com
RFC 8461
Registrar (RDAP) OBSERVED LIVE
MarkMonitor Inc.
Where domain was purchased
Email Service Provider INFERRED
Google Workspace
Strongly 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? No SPF and DMARC reject policy enforced

SPF Record RFC 7208 §4 Verified

Does this domain declare who may send email on its behalf? Yes
Success ~all 8/10 lookups

SPF valid with industry-standard soft fail (~all), 8/10 lookups

v=spf1 ip4:192.30.252.0/22 include:_netblocks.google.com include:_netblocks2.google.com include:_netblocks3.google.com include:spf.protection.outlook.com include:mail.zendesk.com include:_spf.salesforce.com include:servers.mcsv.net include:mktomail.com ip4:62.253.227.114 ip4:166.78.69.169 ip4:166.78.69.170 ip4:166.78.71.131 ip4:167.89.101.2 ip4:167.89.101.192/28 ip4:192.254.112.60 ip4:192.254.112.98/31 ip4:192.254.113.10 ip4:192.254.113.101 ip4:192.254.114.176 ~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 uses ~all + DMARC reject: the strongest compatible security stance, aligned with CISA and RFC guidance.

DMARC Policy RFC 7489 §6.3 Verified

Are spoofed emails rejected or quarantined? Yes — reject policy
Success p=reject

DMARC policy reject (100%) - excellent protection

v=DMARC1; p=reject; pct=100; rua=mailto:dmarc@github.com
Alignment: SPF relaxed DKIM relaxed
No np= tag (DMARCbis) — non-existent subdomains inherit p= policy but adding np=reject provides explicit protection against subdomain spoofing
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
RFC 7489 Conformant — DMARC record conforms to RFC 7489 §6.3 with full enforcement.
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 10 selector(s)

SPF authorizes Microsoft 365 servers, but MX records point to Google Workspace. The Microsoft 365 SPF include likely supports ancillary services (e.g., calendar invitations, shared documents) rather than primary mailbox hosting.
cm._domainkey Campaign Monitor
k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDXLybkpDQnCyQYlQc46kL2sPMsYDqwkjPyFRSDiaq6qUeujAlU775+f8rzxIrjHc8sPstAZOuJzqcgDPiidRxdE2Th/lcnfbN4btWvJwHKK6KD/IazNWNqQtunYyPzfmSRTtOE4Nii4Oxwx1glTJAVhCTObD2uh2U44lCG+pgYswIDAQAB
google._domainkey Google Workspace
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAj6T5sl/RwdSqGoYWaWaFbS2UAeyPrEmd0gogocmRfS441qwR8/0KB81Hw89P0l4YiFRrXYk7NVIGfyCRHAYYZUzCkGeOysI2EjgzLFhd/NEsbRzOEc/kWkK/RO6JFq/5lOn6M9AZw/ap9tds4JG9ApgNNdSpPxp9DmvpsOSgNMVflRxQFrk3kdS4RNAPKu/OPoA7dlR/A/pECryjRoYgENtDXzdnK70HgCekems6UDzxDj61cjyoKoXtEMF/QsaHEQ1Gjfv014rDJBsubk/kT5VqHkWHa/ia68Z5r228Ety/wFfQNjXTx/J7KGZ9GkZlKED659eiJcLnWcKDSiQlhwIDAQAB
k1._domainkey MailChimp
k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDbNrX2cY/GUKIFx2G/1I00ftdAj713WP9AQ1xir85i89sA2guU0ta4UX1Xzm06XIU6iBP41VwmPwBGRNofhBVR+e6WHUoNyIR4Bn84LVcfZE20rmDeXQblIupNWBqLXM1Q+VieI/eZu/7k9/vOkLSaQQdml4Cv8lb3PcnluMVIhQIDAQAB;
k2._domainkey MailChimp
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAv2aC2KjGKLOwTweBY5A9RpjsxaBXR9r7OAU6U8/zn92ivImI75naUujWbItRI/QmL1jy5PWGqLwoUA0b90ObWaLDc+i9MtTNmGeWO009hr20fIxhGg6XBT2kjZ1DTThopSe1nAndsupmcBwlQ5Q6LJ+ZAxLcujnPIxM0ZBLmgpkv8u6RfY4eFP8OLvdAW3oSuB0DyLDigQX4Sj8wBO4YIdQH6AAmBeOsidsKAFNFUCpc3vCxtBDR12U+cBg724l3sBkMQ8evnz6idnqxq9QAVYh8k4kJ+RP+6cqTdy7LjIm8xY/bQNpQIpGUAuDo2DjLcCDun9DAI4Q/3z+Q0o9QuQIDAQAB;
k3._domainkey MailChimp
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYGiMSn7fsUqSvfSX40x9R1OlRtbNiCY80lHRIlcKx3XDIR7257aUx+q9CSIARdfTL6KCuLGNFx5g9TgVr6png4ajcieSQGtOehBgxnkDN8aAA5TX0FmFrcefJU0JoxLOF09EKgXxhSSHCk/ekVb0PXSboHXoZ9+EI404F1qhcwXXIgHXTaUthHTut2P6BBZhIXIgvDe/w49GchR7MRJqjNb7neEBbYHbgWuBTvvHCg7Gy6m6n9krYK+ROWq3dVvXy9plAGK3ygM+HtjIiMt7arRGMOF0WgDTz7YdN9BGpt6BvXxLnjiQcgS5T9n+cIyPZgiWzDMXNlaEEdKTEKxrwIDAQAB;
s1._domainkey SendGrid
k=rsa; t=s; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAyn3fMCVpb7ryIRKOGXhXVGYmsWUitNlSckqGHOwNFZgFadplOrD+Qzf1XQkP7MH/VB/97DsAAJGtEXW1Uq71Hjnfr/DuBN/YfjF/gU70qEFb7q1sdIiNtjFL2TkOpoW+X/bhhPNheW/fYwyFb6ZHFM6LTgXyuimWRHTOUP3VjZzhNVda79nt+2WZYbS4l8HdMgWpTNHjpVw5PtXESA9KBg/evSRk5fIaXIX5eRXW3baoV9yVzD8O29/IL/DiSk+yNvaO0EHL5c4yGuZJhGzvpiznb2IDVdemJK4Dqzdy5FTN/SGYZhAEr7MguG3Z314hMS2scgMsOMgB64uj/6+6UwIDAQAB
s2._domainkey SendGrid
k=rsa; t=s; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnNt2/H6bKs99C6DAaokPp62KN9mKaD20D1PBakkObejkJvzM6Un/fKHPeI2/qXdvFFBPQE3mxMNoe+hwBVDgMgCuZEn8J6gZYI4amITure9/ny6+GaNVRoH2m6xAtWwKINkKxMayGiehkWlRVb7D23F0U8y+VDHKQFz1bnXA5jDpcDiMXy8i2lV5vEys+qt+1WGhDKCAwamT8c3xkZz8aXMJaXYCiN2HMgHDU81+mVCk4+u6mY+a98APVfFhsQ0KCq/mVZXaXTV06QrG9M5PtBHUFW7VtwXKp+AFrAut0KW1NnwaA5IGA5sc+n9dma7bSqdfGS+ixdSmJ69NwmYSHwIDAQAB
smtpapi._domainkey SendGrid
k=rsa; t=s; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDPtW5iwpXVPiH5FzJ7Nrl8USzuY9zqqzjE0D1r04xDN6qwziDnmgcFNNfMewVKN2D1O+2J9N14hRprzByFwfQW76yojh54Xu3uSbQ3JP0A7k8o8GutRF8zbFUA8n0ZH2y0cIEjMliXY4W4LwPA7m4q0ObmvSjhd63O9d8z1XkUBwIDAQAB
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? No reporting
Warning

No TLS-RPT record found

DANE / TLSA Verified Recon Methodology Can mail servers establish identity without a public CA? No
RFC 7672 §3 RFC 6698 §2 Not Available

DANE not available — Google Workspace does not support inbound DANE/TLSA on its MX infrastructure

DANE not deployable on Google Workspace

Google Workspace supports DANE for outbound mail verification but does not publish TLSA records for its MX hosts.

Recommended alternative: MTA-STS

Note: Google Workspace does validate DANE/TLSA when sending mail to DANE-enabled recipients (outbound DANE).

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 has neither DANE nor MTA-STS. Since Google Workspace does not support inbound DANE, deploy MTA-STS (RFC 8461) to enforce TLS and protect against downgrade attacks.

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? Possible DMARC reject policy blocks email spoofing (RFC 7489 §6.3) and CAA restricts certificate issuance (RFC 8659 §4), but no BIMI brand verification — lookalike domains display identically in inboxes without visual proof of authenticity

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

Does this domain restrict who can issue TLS certificates? Yes

CAA configured - only Let's Encrypt, DigiCert, Sectigo, GlobalSign can issue certificates (wildcard issuance: Let's Encrypt, DigiCert, Sectigo per RFC 8659 §4.3)

Authorized CAs: Let's Encrypt DigiCert Sectigo GlobalSign
0 issue "letsencrypt.org"
0 issue "digicert.com"
0 issuewild "letsencrypt.org"
0 issue "sectigo.com"
0 issuewild "digicert.com"
0 issue "globalsign.com"
0 issuewild "sectigo.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? Yes RFC 9116

security.txt properly configured

Contact

https://hackerone.com/github

Expires

unparseable Valid

Policy

https://bounty.github.com
en Canonical URL Hiring Acknowledgments
Source: https://github.com/.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.
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? No No MTA-STS or DANE — mail transport encryption is opportunistic only

All 5 server(s) verified: encrypted transport confirmed via direct SMTP probe and DNS policy

Policy Assessment Primary
  • Google Workspace enforces TLS 1.2+ with valid certificates on all inbound/outbound mail
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
aspmx.l.google.com TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-04-20 (57 days)
Issuer: Google Trust Services
alt3.aspmx.l.google.com TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-04-20 (57 days)
Issuer: Google Trust Services
alt4.aspmx.l.google.com TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-04-20 (57 days)
Issuer: Google Trust Services
alt2.aspmx.l.google.com TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-04-20 (57 days)
Issuer: Google Trust Services
alt1.aspmx.l.google.com TLSv1.3 TLS_AES_256_GCM_SHA384 Valid
Expires: 2026-04-20 (57 days)
Issuer: Google Trust Services
Infrastructure Intelligence Who hosts this domain and what services power it? Direct

ASN / Network Success

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

ASNNameCountry
AS36459 US
IPv4 Mappings:
140.82.112.4 → AS36459 (140.82.112.0/20)

Edge / CDN Success

Domain appears to use direct origin hosting

SaaS TXT Footprint Success 10 services

10 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
Atlassian atlassian-domain-verification=jjgw98AKv2aeoYFxiL/VFaoyPkn3undEssTRuMg6C/3Fp/iqhk...
Microsoft 365 MS=ms44452932
Google Workspace google-site-verification=82Le34Flgtd15ojYhHlGF_6g72muSjamlMVThBOJpks
Stripe stripe-verification=f88ef17321660a01bab1660454192e014defa29ba7b8de9633c69d6b4912...
Loom loom-site-verification=f3787154f1154b7880e720a511ea664d
Adobe adobe-idp-site-verification=b92c9e999aef825edc36e0a3d847d2dbad5b2fc0e05c79ddd7a1...
Apple apple-domain-verification=RyQhdzTl6Z6x8ZP4
Miro miro-verification=d2e174fdb00c71e0bcf58f8e58c3da2dd80dcfa9
Facebook / Meta facebook-domain-verification=39xu4jzl7roi7x0n93ldkxjiaarx50
DocuSign docusign=087098e3-3d46-47b7-9b4e-8a23028154cd
Domain Security Methodology Can DNS responses be tampered with in transit? Possible DNSSEC is not deployed, DNS responses are not cryptographically verified

DNSSEC RFC 4033 §2 Verified Unsigned

DNSSEC not configured - DNS responses are unsigned

Enterprise DNS Context: DNSSEC is the only standardized, DNS-verifiable mechanism that cryptographically authenticates responses between authoritative servers and resolvers (RFC 4033 §2, RFC 4035). Without it, DNS responses are technically vulnerable to in-transit tampering. Enterprise operators may employ compensating controls (anycast, DDoS mitigation, private peering, TSIG) — however, these do not provide DNS-layer data authentication to third-party resolvers and are not verifiable via DNS alone.
Visibility: DNS-only — network-layer compensating controls cannot be observed or verified through DNS queries. This assessment reflects what is provable from the DNS evidence available.

NS Delegation Verified

8 nameserver(s) configured

Nameservers: dns1.p08.nsone.net dns2.p08.nsone.net dns3.p08.nsone.net dns4.p08.nsone.net ns-1283.awsdns-32.org ns-1707.awsdns-21.co.uk ns-421.awsdns-52.com ns-520.awsdns-01.net
Enterprise DNS (Multi-Provider Redundancy)
Nameservers span 2 providers (Amazon Route 53, NS1 (IBM)). Multi-provider DNS provides resilience against single-provider outages — an enterprise best practice for critical domains.
DNS provider(s): Amazon Route 53 NS1 (IBM)
Multi-Resolver Verification Recon: Discrepancy detected - Some resolvers returned different results (5 differences found)
Resolver Differences:
A: OpenDNS returned different results: [140.82.114.4]
A: DNS4EU returned different results: [140.82.121.3]
A: Quad9 returned different results: [140.82.113.3]
A: Google returned different results: [140.82.114.3]
TXT: OpenDNS returned different results: [MS=6BF03E6AF5CB689E315FB6199603BABF2C88D805 MS=ms44452932 MS=ms58704441 TAILSCALE-xOzoDvFUzZr5YYVCQFuD apple-domain-verification=RyQhdzTl6Z6x8ZP4 docusign=087098e3-3d46-47b7-9b4e-8a23028154cd jamf-site-verification=XtaPNIYghF_e_xRDI8CjgQ loom-site-verification=f3787154f1154b7880e720a511ea664d shopify-verification-code=t1YPwcmvnxZyBycaCpk1MPyWoFs72o]
This may indicate DNS propagation in progress or geo-based DNS routing.
Traffic & Routing Where does this domain's traffic actually terminate?

AIPv4 Address

140.82.112.4
Where the domain points for web traffic

AAAAIPv6 Address

No AAAA records
IPv6 not configured

MXMail Servers

1 aspmx.l.google.com.
10 alt3.aspmx.l.google.com.
10 alt4.aspmx.l.google.com.
5 alt2.aspmx.l.google.com.
5 alt1.aspmx.l.google.com.
Priority + mail server for email delivery
Google Workspace

SRVServices

_sipfederationtls._tcp: 10 1 5061 sipfed.online.lync.com.
SIP, XMPP, or other service endpoints
Web: Reachable (1 IPv4, 0 IPv6) Mail: 5 servers Services: 1 endpoint
Subdomain Discovery RFC 6962 Recon LIVE What subdomains and infrastructure are exposed in certificate logs? 70 subdomains discovered
How did we find these?
42 unique certificates 70 current 0 expired 25 CNAMEs Source: Certificate Transparency + DNS Intelligence
Subdomains discovered via CT logs (RFC 6962), DNS probing of common service names, and CNAME chain traversal.
Wildcard certificate detected: *.github.com Active 5 certs 2 CAs: Let's Encrypt, Sectigo Limited
Explicit SANs found on wildcard certificates: These hostnames were specifically listed alongside the wildcard — revealing infrastructure the operator intentionally secured.
www.github.com
DNS probing and CNAME chain traversal were used to discover additional subdomains below.
Certificate Authority Diversity (5 CAs observed across CT log history)
Certificate Authority Certs First Issued Last Issued Status
Sectigo Limited 26 2025-03-07 2026-02-16 Active
Let's Encrypt 8 2025-12-12 2026-02-14 Active
DigiCert Inc 6 2025-06-18 2025-08-22 Active
DigiCert, Inc. 1 2025-09-08 2025-09-08 Active
GlobalSign nv-sa 1 2025-04-26 2025-04-26 Active
Subdomain Source Status Provider / CNAME Certificates First Seen Issuer(s)
admin.github.com DNS Current glb-2a3c35-public-internal.githubapp.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
api.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
api.mcp.github.com CT Log Current glb-db52c2cf8be544.github.com 1 2025-08-22T00:00:00 DigiCert Inc
api.security.github.com CT Log Current glb-db52c2cf8be544.github.com 1 2025-07-31T00:00:00 DigiCert Inc
asset-generator.github.com CT Log Current — 2 2026-01-08T14:25:25 Let's Encrypt
autodiscover.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
blog.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
bug-bash.github.com CT Log Current github.github.io 2 2026-01-07T12:39:04 Let's Encrypt
cloud.github.com DNS Current d24z2fz21y4fag.cloudfront.net 5 2025-03-07 Let's Encrypt, Sectigo Limited
communication.github.com CT Log Current communication.github.com.cname.campaign.adobe.com 2 2025-06-19T00:00:00 DigiCert Inc
community.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
developer.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
developers.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
docs.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
ducky.github.com CT Log Current github.github.io 4 2026-02-14T17:51:09 Let's Encrypt
education.github.com DNS Current glb-db52c2cf8be544.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
emails.github.com CT Log Current — 2 2025-07-06T00:00:00 Sectigo Limited
examadmin-uat.github.com CT Log Current — 8 2025-09-05T00:00:00 Sectigo Limited
examadmin.github.com CT Log Current — 4 2025-09-08T00:00:00 Sectigo Limited
examregistration-api.github.com CT Log Current — 4 2025-09-08T00:00:00 Sectigo Limited
examregistration-uat-api.github.com CT Log Current gh-cert-services-s-uat.azurewebsites.net 4 2025-09-08T00:00:00 Sectigo Limited
examregistration.github.com CT Log Current redirect.github.com 2 2025-09-08T00:00:00 DigiCert, Inc.
f.cloud.github.com CT Log Current — 2 2025-04-26T20:00:54 GlobalSign nv-sa
forms.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
garage.github.com CT Log Current — 2 2025-09-15T00:00:00 Sectigo Limited
gist.github.com CT Log Current github.com 2 2025-09-15T00:00:00 Sectigo Limited
github.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
help.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
hub.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
import2.github.com CT Log Current — 2 2025-07-02T00:00:00 Sectigo Limited
importer2.github.com CT Log Current — 2 2025-07-02T00:00:00 Sectigo Limited
jobs.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
learn.github.com DNS Current glb-db52c2cf8be544.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
live.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
livesend.github.com CT Log Current — 2 2026-02-07T08:43:37 Let's Encrypt
m.communication.github.com CT Log Current — 1 2025-06-19T00:00:00 DigiCert Inc
mailing.github.com CT Log Current — 4 2026-02-08T00:00:00 Sectigo Limited
media.github.com DNS Current alambic-origin.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
model-launchkit.github.com CT Log Current github.github.io 2 2026-01-20T09:21:38 Let's Encrypt
mona-arcade.github.com CT Log Current github.github.io 2 2025-12-12T08:25:51 Let's Encrypt
ns1.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
ns2.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
octocaptcha.review-lab.github.com CT Log Current — 4 2025-06-03T00:00:00 Sectigo Limited
partner.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
pkg.github.com CT Log Current — 8 2026-02-08T00:00:00 Sectigo Limited
policy.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
porter2.github.com CT Log Current — 2 2025-07-02T00:00:00 Sectigo Limited
redirect.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
registry.github.com CT Log Current — 8 2026-02-16T00:00:00 Sectigo Limited
res.communication.github.com CT Log Current — 1 2025-06-19T00:00:00 DigiCert Inc
review-lab.github.com CT Log Current — 8 2026-02-08T00:00:00 Sectigo Limited
services.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
shop.github.com DNS Current github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
slack.github.com DNS Current glb-db52c2cf8be544.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
smtp.github.com CT Log Current — 4 2025-06-29T00:00:00 Sectigo Limited
ssh.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
status.github.com DNS Current redirect.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
support.enterprise.github.com CT Log Current — 1 2025-07-31T00:00:00 DigiCert Inc
support.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
t.communication.github.com CT Log Current — 1 2025-06-19T00:00:00 DigiCert Inc
teams.github.com DNS Current glb-db52c2cf8be544.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
test.github.com DNS Current — 5 2025-03-07 Let's Encrypt, Sectigo Limited
training.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
uploads.github.com DNS Current alambic-origin.githubusercontent.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
vpn-ca.iad.github.com CT Log Current github.github.io 2 2026-01-18T00:00:00 Sectigo Limited
warehouse.github.com DNS Current github.github.io 5 2025-03-07 Let's Encrypt, Sectigo Limited
wiki.github.com DNS Current raw-origin.github.com 5 2025-03-07 Let's Encrypt, Sectigo Limited
ws.support.github.com CT Log Current — 1 2025-07-31T00:00:00 DigiCert Inc
www.communication.github.com CT Log Current — 1 2025-06-18T00:00:00 DigiCert Inc
www.github.com CT Log Current github.com 10 2026-02-08T00:00:00 Sectigo Limited
Export Recon (CSV)
Δ Changes Detected: A Resolver ≠ Authoritative (TTL / CDN rotation / recent change)
Risk: Low - typically resolves within TTL
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 Propagating 1 / 1 records
140.82.112.4
140.82.114.3
AAAA 0 / 0 records
No records
No records
CAA RFC 8659 §4 Synchronized 7 / 7 records
0 issue "globalsign.com"
0 issue "digicert.com"
0 issue "sectigo.com"
0 issue "globalsign.com"
0 issuewild "digicert.com"
0 issue "letsencrypt.org"
0 issuewild "letsencrypt.org"
0 issue "sectigo.com"
0 issue "letsencrypt.org"
0 issuewild "digicert.com"
0 issue "digicert.com"
0 issuewild "letsencrypt.org"
0 issuewild "sectigo.com"
0 issuewild "sectigo.com"
DMARC _dmarc.github.com RFC 7489 §6.3 Synchronized 1 / 1 records
v=DMARC1; p=reject; pct=100; rua=mailto:dmarc@github.com
v=DMARC1; p=reject; pct=100; rua=mailto:dmarc@github.com
MX RFC 5321 Synchronized 5 / 5 records
1 aspmx.l.google.com.
1 aspmx.l.google.com.
10 alt3.aspmx.l.google.com.
5 alt1.aspmx.l.google.com.
10 alt4.aspmx.l.google.com.
5 alt2.aspmx.l.google.com.
5 alt2.aspmx.l.google.com.
10 alt3.aspmx.l.google.com.
5 alt1.aspmx.l.google.com.
10 alt4.aspmx.l.google.com.
NS RFC 1035 Synchronized 8 / 8 records
ns-421.awsdns-52.com.
dns1.p08.nsone.net.
ns-520.awsdns-01.net.
dns2.p08.nsone.net.
dns2.p08.nsone.net.
dns3.p08.nsone.net.
ns-1283.awsdns-32.org.
dns4.p08.nsone.net.
ns-1707.awsdns-21.co.uk.
ns-1283.awsdns-32.org.
dns3.p08.nsone.net.
ns-1707.awsdns-21.co.uk.
dns4.p08.nsone.net.
ns-421.awsdns-52.com.
dns1.p08.nsone.net.
ns-520.awsdns-01.net.
SOA RFC 1035 Synchronized 1 / 1 records
dns1.p08.nsone.net. hostmaster.nsone.net. 1656468023 43200 7200 1209600 3600
dns1.p08.nsone.net. hostmaster.nsone.net. 1656468023 43200 7200 1209600 3600
TXT RFC 7208 §4 19 / 0 records
atlassian-domain-verification=jjgw98AKv2aeoYFxiL/VFaoyPkn3undEssTRuMg6C/3Fp/iqhkV4HVV7WjYlVeF8
—
jamf-site-verification=XtaPNIYghF_e_xRDI8CjgQ
—
TAILSCALE-xOzoDvFUzZr5YYVCQFuD
—
MS=ms44452932
—
google-site-verification=82Le34Flgtd15ojYhHlGF_6g72muSjamlMVThBOJpks
—
stripe-verification=f88ef17321660a01bab1660454192e014defa29ba7b8de9633c69d6b4912217f
—
loom-site-verification=f3787154f1154b7880e720a511ea664d
—
krisp-domain-verification=ZlyiK7XLhnaoUQb2hpak1PLY7dFkl1WE
—
v=spf1 ip4:192.30.252.0/22 include:_netblocks.google.com include:_netblocks2.google.com include:_netblocks3.google.com include:spf.protection.outlook.com include:mail.zendesk.com include:_spf.salesforce.com include:servers.mcsv.net include:mktomail.com ip4:62.253.227.114 ip4:166.78.69.169 ip4:166.78.69.170 ip4:166.78.71.131 ip4:167.89.101.2 ip4:167.89.101.192/28 ip4:192.254.112.60 ip4:192.254.112.98/31 ip4:192.254.113.10 ip4:192.254.113.101 ip4:192.254.114.176 ~all
—
calendly-site-verification=at0DQARi7IZvJtXQAWhMqpmIzpvoBNF7aam5VKKxP
—
MS=6BF03E6AF5CB689E315FB6199603BABF2C88D805
—
google-site-verification=UTM-3akMgubp6tQtgEuAkYNYLyYAvpTnnSrDMWoDR3o
—
adobe-idp-site-verification=b92c9e999aef825edc36e0a3d847d2dbad5b2fc0e05c79ddd7a16139b48ecf4b
—
apple-domain-verification=RyQhdzTl6Z6x8ZP4
—
MS=ms58704441
—
miro-verification=d2e174fdb00c71e0bcf58f8e58c3da2dd80dcfa9
—
facebook-domain-verification=39xu4jzl7roi7x0n93ldkxjiaarx50
—
shopify-verification-code=t1YPwcmvnxZyBycaCpk1MPyWoFs72o
—
docusign=087098e3-3d46-47b7-9b4e-8a23028154cd
—
DNS History Timeline BETA
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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.

ce8aa57b9cd09c85fdd625fa86dce896fd34557b55a229ce23f1414d21c397a62c87bc1d94561983cc90e1a9151063c2d482c52ca589d3d1c3367b283f5f0f47
Evaluations reference 12 RFCs. Methods are reproducible using the verification commands provided. Results reflect DNS state at 22 Feb 2026, 04:20 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-github.com.json.sha3 && echo '---' && openssl dgst -sha3-512 dns-intelligence-github.com.json
Python 3 (cross-platform) 
python3 -c "import hashlib; print(hashlib.sha3_512(open('dns-intelligence-github.com.json','rb').read()).hexdigest())"
sha3sum (coreutils 9+) 
sha3sum -a 512 dns-intelligence-github.com.json
Compare the output against the .sha3 file or the checksum API at /api/analysis/3575/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 github.com. 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 github.com A
Query AAAA records (IPv6) RFC 1035 
dig +noall +answer github.com AAAA
Query MX records (mail servers) RFC 1035 
dig +noall +answer github.com MX
Query NS records (nameservers) RFC 1035 
dig +noall +answer github.com NS
Query TXT records RFC 1035 
dig +noall +answer github.com TXT

Email Authentication

Check SPF record RFC 7208 
dig +short github.com TXT | grep -i spf
Check DMARC policy RFC 7489 
dig +short _dmarc.github.com TXT
Check DKIM key for selector 'cm' RFC 6376 
dig +short cm._domainkey.github.com TXT
Check DKIM key for selector 'google' RFC 6376 
dig +short google._domainkey.github.com TXT
Check DKIM key for selector 'k1' RFC 6376 
dig +short k1._domainkey.github.com TXT
Check DKIM key for selector 'k2' RFC 6376 
dig +short k2._domainkey.github.com TXT
Check DKIM key for selector 'k3' RFC 6376 
dig +short k3._domainkey.github.com TXT
Check DKIM key for selector 's1' RFC 6376 
dig +short s1._domainkey.github.com TXT
Check DKIM key for selector 's2' RFC 6376 
dig +short s2._domainkey.github.com TXT
Check DKIM key for selector 'smtpapi' RFC 6376 
dig +short smtpapi._domainkey.github.com TXT
Check DKIM key for selector 'zendesk1' RFC 6376 
dig +short zendesk1._domainkey.github.com TXT
Check DKIM key for selector 'zendesk2' RFC 6376 
dig +short zendesk2._domainkey.github.com TXT

Domain Security

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

Transport Security

Check TLSA record for aspmx.l.google.com RFC 7672 
dig +noall +answer _25._tcp.aspmx.l.google.com TLSA
Check TLSA record for alt3.aspmx.l.google.com RFC 7672 
dig +noall +answer _25._tcp.alt3.aspmx.l.google.com TLSA
Check TLSA record for alt4.aspmx.l.google.com RFC 7672 
dig +noall +answer _25._tcp.alt4.aspmx.l.google.com TLSA
Check TLSA record for alt2.aspmx.l.google.com RFC 7672 
dig +noall +answer _25._tcp.alt2.aspmx.l.google.com TLSA
Check TLSA record for alt1.aspmx.l.google.com RFC 7672 
dig +noall +answer _25._tcp.alt1.aspmx.l.google.com TLSA
Verify TLS certificate on primary MX (aspmx.l.google.com) RFC 6698 
openssl s_client -starttls smtp -connect aspmx.l.google.com:25 -servername aspmx.l.google.com 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record RFC 8461 
dig +short _mta-sts.github.com TXT
Fetch MTA-STS policy file RFC 8461 
curl -sL https://mta-sts.github.com/.well-known/mta-sts.txt
Check TLS-RPT record RFC 8460 
dig +short _smtp._tls.github.com TXT

Brand & Trust

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

DNS Records

Check HTTPS/SVCB records RFC 9460 
dig +noall +answer github.com HTTPS

Domain Security

Check CDS/CDNSKEY automation records RFC 7344 
dig +noall +answer github.com CDS

Infrastructure Intelligence

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

Transport Security

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

Infrastructure Intelligence

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

AI Surface

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

Infrastructure Intelligence

ASN lookup for 140.82.112.4 (Team Cymru) 
dig +short 4.112.82.140.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 4849 runs
DKIM
Verified 4668 runs
DMARC
Verified 4833 runs
DANE/TLSA
Verified 4652 runs
DNSSEC
Verified 4830 runs
BIMI
Verified 4667 runs
MTA-STS
Verified 4670 runs
TLS-RPT
Verified 4672 runs
CAA
Verified 4664 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 github.com A
Query AAAA records (IPv6) (RFC 1035) 
dig +noall +answer github.com AAAA
Query MX records (mail servers) (RFC 1035) 
dig +noall +answer github.com MX
Query NS records (nameservers) (RFC 1035) 
dig +noall +answer github.com NS
Query TXT records (RFC 1035) 
dig +noall +answer github.com TXT

Email Authentication

Check SPF record (RFC 7208) 
dig +short github.com TXT | grep -i spf
Check DMARC policy (RFC 7489) 
dig +short _dmarc.github.com TXT
Check DKIM key for selector 'cm' (RFC 6376) 
dig +short cm._domainkey.github.com TXT
Check DKIM key for selector 'google' (RFC 6376) 
dig +short google._domainkey.github.com TXT
Check DKIM key for selector 'k1' (RFC 6376) 
dig +short k1._domainkey.github.com TXT
Check DKIM key for selector 'k2' (RFC 6376) 
dig +short k2._domainkey.github.com TXT
Check DKIM key for selector 'k3' (RFC 6376) 
dig +short k3._domainkey.github.com TXT
Check DKIM key for selector 's1' (RFC 6376) 
dig +short s1._domainkey.github.com TXT
Check DKIM key for selector 's2' (RFC 6376) 
dig +short s2._domainkey.github.com TXT
Check DKIM key for selector 'smtpapi' (RFC 6376) 
dig +short smtpapi._domainkey.github.com TXT
Check DKIM key for selector 'zendesk1' (RFC 6376) 
dig +short zendesk1._domainkey.github.com TXT
Check DKIM key for selector 'zendesk2' (RFC 6376) 
dig +short zendesk2._domainkey.github.com TXT

Domain Security

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

Transport Security

Check TLSA record for aspmx.l.google.com (RFC 7672) 
dig +noall +answer _25._tcp.aspmx.l.google.com TLSA
Check TLSA record for alt3.aspmx.l.google.com (RFC 7672) 
dig +noall +answer _25._tcp.alt3.aspmx.l.google.com TLSA
Check TLSA record for alt4.aspmx.l.google.com (RFC 7672) 
dig +noall +answer _25._tcp.alt4.aspmx.l.google.com TLSA
Check TLSA record for alt2.aspmx.l.google.com (RFC 7672) 
dig +noall +answer _25._tcp.alt2.aspmx.l.google.com TLSA
Check TLSA record for alt1.aspmx.l.google.com (RFC 7672) 
dig +noall +answer _25._tcp.alt1.aspmx.l.google.com TLSA
Verify TLS certificate on primary MX (aspmx.l.google.com) (RFC 6698) 
openssl s_client -starttls smtp -connect aspmx.l.google.com:25 -servername aspmx.l.google.com 2>/dev/null | openssl x509 -noout -subject -dates
Check MTA-STS DNS record (RFC 8461) 
dig +short _mta-sts.github.com TXT
Fetch MTA-STS policy file (RFC 8461) 
curl -sL https://mta-sts.github.com/.well-known/mta-sts.txt
Check TLS-RPT record (RFC 8460) 
dig +short _smtp._tls.github.com TXT

Brand & Trust

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

DNS Records

Check HTTPS/SVCB records (RFC 9460) 
dig +noall +answer github.com HTTPS

Domain Security

Check CDS/CDNSKEY automation records (RFC 7344) 
dig +noall +answer github.com CDS

Infrastructure Intelligence

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

Transport Security

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

Infrastructure Intelligence

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

AI Surface

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

Infrastructure Intelligence

ASN lookup for 140.82.112.4 (Team Cymru) 
dig +short 4.112.82.140.origin.asn.cymru.com TXT
Running Multi-Source Intelligence Audit

github.com

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.