DKIM, SPF , DMARC

SPF (Sender Policy Framework)

This validates who is allowed to send emails from the domain, such as email servers and such, if there is an external institute handling this then, a TXT Record will be configured on the domain.

This is checked when the Simple Mail Transfer Protocol (SMTP) server talk with each other

DKIM (Domain Key Identified Mail)

This is a way to ensure that the email that has been sent by an domain, is actually owned by the domain or not, this is done through cryptographic signatures, where the email sent along with a signature which can later be verified on the receiving end .

DKIM

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