June 15, 2026
What is DKIM, and how does it prove an email wasn't tampered with?
DKIM (RFC 6376) explained: the cryptographic signature, the DNS record, selectors, rotation, 1024 vs 2048 bits, and why DMARC is still needed.
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June 14, 2026
What is SPF, and how does it authorize sending servers?
A plain-English guide to SPF (RFC 7208): what it is, the DNS record, the include/ip4/a/mx mechanisms, the 10-lookup limit, and why SPF alone isn't enough.
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