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3 articles
SPF ~all vs -all vs ?all
Soft fail, hard fail, neutral and pass-all: what each SPF qualifier on the all mechanism actually instructs receivers to do, how DMARC changes the picture, and which one to publish at each stage of your rollout.
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SPF flattening: what it is and when you need it
SPF flattening replaces lookup-based mechanisms with raw IP ranges to dodge the ten-lookup limit. It works, but a hand-flattened record silently goes stale. Here is what flattening really does, the trade-offs, why doing it by hand is risky, and how hosted flattening stays current automatically.
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SPF records for common email providers
The correct, current SPF includes for Google Workspace, Microsoft 365, Mailchimp, SendGrid, Amazon SES and more, plus how to combine several providers in one record without breaking the 10-lookup limit.
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