Reviewed by: QuickDMARC Security Team · Email Authentication Specialists · Last reviewed: 2026-08-31

Prevent Email Spoofing

Email spoofing occurs when attackers forge the From address to impersonate your brand. DMARC at p=reject blocks spoofed messages that fail SPF/DKIM alignment checks.

Why spoofing happens

SMTP was designed without sender authentication. Anyone can set a From header to any address. Without DMARC enforcement, receiving servers cannot reliably reject forged messages.

How to stop spoofing

1. Publish SPF listing all authorized sending IPs and includes (RFC 7208)
2. Enable DKIM signing on all outbound mail paths (RFC 6376)
3. Publish DMARC starting at p=none, monitor, then enforce p=reject (RFC 7489)
4. Monitor aggregate reports for unauthorized senders

Additional protections

Combine DMARC with BIMI (brand logo display), MTA-STS (transport security), and TLS-RPT for defense in depth. QuickDMARC monitors all authentication signals from a single dashboard.