Why You Need All Three
SPF, DKIM, and DMARC work together. SPF says WHO can send. DKIM proves the message wasn't altered. DMARC tells receivers what to do when checks fail.
Setting Up SPF
1. List your senders: Your mail server, ESP (Mailchimp, etc.), transactional (SendGrid, etc.)
2. Create TXT record:v=spf1 include:_spf.google.com include:sendgrid.net -all
Tips:
- Use -all (hard fail) not ~all (soft fail)
- Keep under 10 DNS lookups
- Don't use +all ever
Setting Up DKIM and DMARC
DKIM: Generate keys through your email provider. Add the public key as a TXT record at selector._domainkey.yourdomain.com
DMARC: Start with monitoring mode:v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com
After reviewing reports, move to quarantine then reject:v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com
Check your configuration with our free email security tool.