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CompTIA SecurityX CAS-005 · Domain 3: Security engineering

Email and DNS security engineering: SPF, DKIM, DMARC, DNSSEC and S/MIME

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Last reviewed September 25, 2026 · Leer en español

Email and DNS are old protocols built without strong authentication, and attackers abuse them for phishing, spoofing and redirection. Several DNS-published standards add the missing checks, and SecurityX expects you to know how they fit together and roll them out safely.

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