Configuring DMARC p=quarantine: A Technical Step-by-Step Guide to Secure Your Domain and Improve Deliverability

DMARC is an email authentication protocol defined in RFC 7489 that builds upon SPF and DKIM to protect domains from unauthorized use. It allows domain owners to specify how receiving mail servers handle unauthenticated emails via DNS policies. The protocol includes reporting mechanisms: Aggregate Reports (RUA) provide high-level overviews of authentication results and sending sources, while Forensic Reports (RUF) assist in postmaster debugging. Policies like p=quarantine dictate specific actions for emails failing authentication.