How to set up DMARC for Google Workspace

DMARC (RFC 7489) tells receiving mail servers what to do when a message claiming to be from your domain fails SPF or DKIM. You publish exactly one DMARC record at `_dmarc.<your-domain>`, regardless of which ESP you use — DMARC is a domain-level policy, not a per-sender configuration. Google Workspace doesn't run DMARC for you, but their SPF + DKIM setup is what makes your DMARC checks pass.

Start every domain at `p=none` with a `rua` (aggregate report) address pointing somewhere you actually read. Watch the reports for two to four weeks to confirm 100% of legitimate mail is aligned, then progress to `p=quarantine` and finally `p=reject`. Skipping the monitoring step is the single most common way founders accidentally block their own mail.

Publish these DNS records

Add the following record(s) to your domain's DNS zone. Most registrars (Cloudflare, Route 53, Namecheap, GoDaddy) accept values exactly as shown.

• Replace the `rua=` address with one you read. MailerMonk users get a managed reporting address that aggregates and parses these reports for you.
• Strict alignment (`adkim=s; aspf=s`) is fine for Google Workspace because Google's signing aligns the From: domain with the DKIM `d=` tag by default.

Where in Google Workspace

The DMARC configuration lives in Admin console → Apps → Google Workspace → Gmail → Authenticate email.

Verify the records

Once published, run the DMARC Checker on your apex domain to confirm the record parses, reporting URIs are valid, and the policy is what you intended.

Common pitfalls

• Generating a new DKIM key in the Admin console rotates the key — old signatures stay valid until they expire, but verify mail still signs cleanly afterwards.
• If you've migrated from another provider and inherited an SPF record with conflicting includes, Google's authentication check will appear to pass while DMARC still fails alignment. Always check the DMARC report, not just the Admin console green checkmark.