DMARC

DMARC stands for Domain-based Message Authentication, Reporting and Conformance.

It is an email authentication protocol that builds on SPF and DKIM. DMARC allows domain owners to:

• Tell receiving mail servers how to handle unauthenticated mail claiming to be from their domain
• Receive reports about who is sending emails using their domain (legitimately or not)

---

🔍 How DMARC Works

1. A mail server receives an email claiming to be from example.com
2. It checks whether the email passes SPF or DKIM
3. It verifies that the domain in SPF/DKIM aligns with the From: address
4. It consults the DMARC record (in DNS) to decide what to do:
   • Accept the email
   • Mark it as spam (quarantine)
   • Reject it entirely

---

🧾 Example DMARC Record

_dmarc.example.com. IN TXT "v=DMARC1; p=reject; rua=mailto:dmarc@example.com"

• v=DMARC1 → Version
• p=reject → Reject emails that fail DMARC
• rua=... → Send aggregate reports here

---

✅ TL;DR

DMARC stands for	Domain-based Message Authentication, Reporting and Conformance
Used for	Controlling what happens to emails that fail SPF/DKIM
Type of DNS record	TXT at _dmarc.yourdomain.com
Helps protect against	Spoofing, phishing, brand abuse
Works with	SPF, DKIM, DNS