DMARC stops exact-domain spoofing, so attackers moved to lookalikes. It is now the dominant brand-impersonation technique.
The metrics that matter#
- Authentication pass rate: share of mail passing SPF, DKIM, and DMARC alignment. Healthy: 99% or higher.
- Spam complaint rate: Gmail enforces at 0.3%; stay under 0.1%.
- Hard bounce rate: under 2%; above 5% triggers platform reviews.
- Inbox placement: above 90% across major providers via seed tests.
- Engagement: click and reply rates by segment; opens are unreliable after Mail Privacy Protection.
Where to read them#
- Google Postmaster Tools for Gmail domain reputation, spam rate, and authentication.
- Microsoft SNDS and JMRP for Outlook.com IP reputation and complaints.
- Your ESP's delivery and bounce reports.
- DMARC aggregate reports for authentication by source.
Improving the numbers#
- Register the most obvious typo and hyphen variants of your domain.
- Monitor new registrations that contain your brand string.
- Configure inbound gateway rules to flag display names matching executives from external domains.
- Train finance and executive assistants specifically on this pattern.
Frequently asked questions#
How many lookalike domains should I register?
The top 10 to 20 variants by likelihood is a reasonable start; monitoring covers the long tail.