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When a subdomain of your domain does not have its own DMARC record published, the "sp" tag specifies the policy to be applied to emails specifically sent from that subdomain. This allows you to enforce a unique DMARC policy across each subdomains of a domain. If the "sp" tag is not explicitly set in the DMARC record, the DMARC policy specified by the "p" tag (the organizational domain's policy) is applied to emails sent from subdomains without their own DMARC records.
DMARC ADKIM ADKIM -
The "adkim" tag stands for "Alignment Mode for DKIM." It specifies how the DKIM mail signatures should align with the email's From domain, and can have two values:
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