DMARC policies best practices for nonprofits

Donor lists age quickly; re-engagement and sunset policies protect reputation.

What DMARC policies are#

DMARC (Domain-based Message Authentication, Reporting and Conformance) tells receivers what to do when a message fails SPF and DKIM alignment, and asks them to send aggregate and forensic reports back to the domain owner.

Why it matters#

DMARC at p=reject is what actually stops exact-domain spoofing. Gmail and Yahoo require at least p=none for bulk senders, and BIMI requires p=quarantine or p=reject.

Implementation plan for nonprofits#

1. Confirm SPF and DKIM are deployed and aligned for every legitimate sender.
2. Publish _dmarc.yourdomain.com with v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com to begin collecting reports.
3. Analyze aggregate (RUA) reports for 2 to 4 weeks to identify unauthenticated legitimate sources.
4. Fix each source, then move to p=quarantine with pct=25, ramping to 100.
5. Move to p=reject and add sp=reject to cover subdomains.

_dmarc.example.com.  IN TXT  "v=DMARC1; p=reject; sp=reject; rua=mailto:dmarc-rua@example.com; adkim=s; aspf=s; pct=100"

Priorities specific to nonprofits#

Donor lists age quickly; re-engagement and sunset policies protect reputation. Weight your effort toward the steps above that address this constraint first, and measure with metrics that match how nonprofits generate value from email.

Common mistakes#

• Jumping straight to p=reject and blocking your own invoicing or HR system.
• Sending RUA reports to a mailbox nobody reads; use a report processor.
• Leaving subdomains uncovered because sp= was never set.
• Assuming p=none provides protection; it is monitoring only.

Frequently asked questions#