Executive's DNS Intelligence Brief

DMARC (Domain-based Message Authentication, Reporting & Conformance) tells receivers how to handle messages that fail SPF/DKIM checks. Without DMARC, failed authentication checks are ignored. Start with p=none and rua reporting to monitor, then escalate to p=quarantine and p=reject.

Publish CAA DNS records to restrict which Certificate Authorities can issue TLS certificates for your domain. Specify your preferred CA (e.g., letsencrypt.org, digicert.com).

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

Your SPF record uses ~all (softfail), which asks receivers to accept but flag unauthorized senders. Upgrading to -all (hardfail) instructs receivers to reject unauthorized senders outright. Verify all legitimate sending sources are included before switching. Note: if you later enable DMARC enforcement (p=reject or p=quarantine) with DKIM, ~all becomes acceptable because DMARC evaluates both SPF and DKIM alignment before making decisions (RFC 7489 §10.1).

TLS-RPT (TLS Reporting) sends you reports about TLS connection failures when other servers try to deliver mail to your domain. Helps diagnose MTA-STS and STARTTLS issues.

DNSSEC (DNS Security Extensions) cryptographically signs DNS responses, preventing attackers from forging DNS answers. Contact your DNS hosting provider to enable DNSSEC signing.