模块课程（1/3）
SPF, DKIM e DMARC
SPF, DKIM, and DMARC
Specifications: SPF, RFC 7208, DKIM, RFC 6376, and DMARC, RFC 9989. RFC 9989 is the latest DMARC specification and obsoletes RFC 7489.
These email mechanisms use DNS records, often TXT, but each has a different job. SPF describes which systems may send mail for a domain. DKIM lets a receiver verify a message signature using a public key published in DNS. DMARC uses alignment rules and a domain policy to guide handling and reporting. A DNS record alone does not guarantee that a message is trustworthy.
Review syntax, alignment, policy, and reporting together. Roll out enforcement carefully, monitor legitimate senders, and avoid publishing multiple conflicting SPF records for the same name.
Check your understanding
Choose the best answer. This quiz runs locally and sends no DNS queries to real domains.
Which protocol publishes a public key in DNS to verify an email signature?