DNS for Email: Keeping Bookstore's Mail Out of Spam with MX, SPF, DKIM and DMARC
Passing SPF or DKIM is not enough to keep mail out of spam; DMARC requires the passing domain to align with the From: domain the user sees, and Gmail, Yahoo and Outlook require this of bulk senders. In a lab we set up Bookstore's MX, SPF, DKIM and DMARC records, sign and verify an order mail with real libraries, and see that the 10-lookup limit breaks only for some IPs and why a provider's default DKIM fails DMARC.
14 Nov 2026
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14 min
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2
