Guides
Guides to email security, in plain English.
Plain-English guides: what Gmail, Yahoo and Microsoft require of senders, how SPF, DKIM and DMARC fit together, and DMARC on Microsoft 365.
3 min read
Gmail, Yahoo and Microsoft sender rules, in plain English
What Gmail, Yahoo and Microsoft require of anyone sending email, since when, and what happens to mail that fails.
Read the guide5 min read
SPF, DKIM and DMARC explained
What SPF, DKIM and DMARC each do, how they work together and the mistakes that quietly undo them.
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Set up DMARC on Microsoft 365
How to set up DMARC on Microsoft 365 in a safe order, from checking SPF and DKIM to tightening the policy.
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