Definition

DMARC tells receiving mail servers what to do when SPF or DKIM fail, and sends you aggregate reports about authentication results for your domain.

Detailed Explanation

DNS record on _dmarc.yourdomain.com:

v=DMARC1; p=none; rua=mailto:reports@yourdomain.com; pct=100

Policy levels:

  • p=none — monitor only (start here)
  • p=quarantine — send failures to spam
  • p=reject — block failures entirely

Reports (rua) show which sources send as your domain — essential for catching spoofing and misconfigured ESPs.

Nepal Context

Implement DMARC before scaling email marketing beyond a few hundred subscribers. Start with p=none, review reports for 2–4 weeks, then tighten policy.

Key Takeaways

  • DMARC requires SPF and/or DKIM alignment
  • Progress: none → quarantine → reject
  • Monitor aggregate reports weekly

Common Mistakes

  1. Jumping to p=reject without monitoring
  2. No report email configured (rua)
  3. SPF/DKIM not aligned with From domain