Guides
SPF, DKIM & DMARC setup guide
Set up all three email authentication standards for Microsoft 365 or Google Workspace, and get to p=reject safely.
Microsoft 365 email security
Exact Defender portal steps and copy-paste records for an M365 tenant: SPF, selector1/selector2 DKIM, DMARC to p=reject, MTA-STS.
Google Workspace email security
Admin console steps and copy-paste records for Workspace: SPF, 2048-bit DKIM, DMARC to p=reject, MTA-STS.
DNS security checklist
A practical checklist for hardening a business domain: registrar locks, DNSSEC, CAA, nameserver hygiene.