usefulweb.site E-mail Infrastructure Explorer

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E-mail Infrastructure Explorer

MX, SPF lookups, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI for a domain, scored with fixes.

Zone-file lines: name [ttl] [IN] TYPE value. Use @ for the domain, relative names like _dmarc or selector1._domainkey, and a trailing dot for other domains (e.g. include targets).

Try an example: Pasted records for a typical business domain

How it works

Checks how a domain receives and protects e-mail: MX hosts with priorities and addresses, SPF with a recursive DNS-lookup count across include: chains, DMARC policy and reporting, DKIM keys at ten common selectors, MTA-STS record and policy file, TLS-RPT and BIMI. Produces a transparent 100-point score and concrete DNS fixes. Works live or on pasted zone records.

  • DNS: MX (+ A/AAAA of each exchange), TXT at the domain, _dmarc, <selector>._domainkey for default, google, selector1, selector2, k1, s1, s2, mail, dkim, mx, _mta-sts, _smtp._tls and default._bimi.
  • SPF (RFC 7208): include: and redirect= are followed recursively; include, a, mx, ptr, exists and redirect each cost one DNS lookup, more than 10 in total is a permerror; more than 2 void lookups is also an error.
  • DMARC (RFC 7489) policy, pct and rua. DKIM (RFC 6376): key type and RSA modulus length decoded from p=; empty p= means revoked. Real selectors are chosen by the sender and cannot be enumerated, so "none found" is not proof that DKIM is absent.
  • MTA-STS (RFC 8461): TXT v=STSv1 plus the policy at https://mta-sts.<domain>/.well-known/mta-sts.txt; each MX must match a policy mx: pattern. TLS-RPT (RFC 8460) v=TLSRPTv1 with rua. BIMI needs DMARC quarantine/reject at 100 %.
  • Score (100): MX 10, SPF 20, DMARC 25, DKIM 15, MTA-STS 15, TLS-RPT 10, BIMI 5. Domains with a null MX (no inbound mail) are scored only on SPF and DMARC, scaled to 100.

For scripts and AI agents

  • JSON API: POST https://emailinfrastructureexplorer.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://emailinfrastructureexplorer.usefulweb.site/mcp · tool name email_infrastructure_explorer
Example request
curl -s -X POST https://emailinfrastructureexplorer.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{…see OpenAPI examples…}'

Related tools

  • DNS + Certificate Explorer – DNS records, e-mail security, CAA, live TLS certificate and CT history for a domain.
  • Domain History Graph – Registration, DNS, hosting networks, certificates and Wayback captures of a domain as a timeline.
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