SPF vs DKIM vs DMARC: The Complete Deliverability Guide & Setup

1. Sender Policy Framework (SPF)

SPF specifies which mail servers are authorized to send email on behalf of your domain. It is published as a DNS TXT record at the root domain.

v=spf1 include:_spf.google.com ~all

2. DomainKeys Identified Mail (DKIM)

DKIM adds a cryptographic signature to emails. Receivers verify the signature against the public key published in your DNS under a specific selector host (e.g. google._domainkey.yourdomain.com).

3. DMARC Alignment & Enforcement

DMARC ties SPF and DKIM together. It specifies how mailbox providers (Gmail, Outlook, Yahoo) should handle unauthenticated emails using three policies:

• p=none: Monitoring mode only
• p=quarantine: Direct failing emails to spam
• p=reject: Block non-compliant emails completely