Question 1

What is DMARC?

Accepted Answer

DMARC (Domain-based Message Authentication, Reporting and Conformance) is an email authentication protocol that builds on SPF and DKIM. It tells receiving servers what to do when SPF or DKIM checks fail: none (monitor), quarantine, or reject.

Question 2

What DMARC policy should I use?

Accepted Answer

Start with p=none to monitor without affecting delivery. Once you've confirmed all legitimate sources pass SPF/DKIM, move to p=quarantine, then p=reject for maximum protection against spoofing.

Question 3

What are DMARC aggregate reports (rua)?

Accepted Answer

The rua tag specifies where receiving servers should send XML aggregate reports about email authentication results. These reports help you understand who is sending email on behalf of your domain.

Question 4

What is DMARC alignment?

Accepted Answer

DMARC checks that the domain in the From header aligns with the domain authenticated by SPF (envelope sender) or DKIM (d= domain). Alignment can be 'strict' (exact match) or 'relaxed' (organizational domain match).

Question 5

Why is DMARC important for email deliverability?

Accepted Answer

DMARC is required by major mailbox providers (Google, Yahoo, Microsoft) for bulk senders. Without DMARC, your emails are more likely to land in spam. A proper DMARC policy also protects your domain from being used in phishing attacks.