SSL MOON

DMARC (Domain-based Message Authentication, Reporting and Conformance) is a DNS TXT record at _dmarc that tells receiving mail servers how to handle messages that fail SPF or DKIM, and where to send reports.

An enforcing DMARC policy is published (p=reject).
DMARC record v=DMARC1; p=reject; sp=reject; pct=100; ruf=mailto:dmarc@stisc.gov.md; rua=mailto:dmarc@stisc.gov.md; adkim=r; aspf=r; fo=1