DKIM
DKIM (DomainKeys Identified Mail) is an email authentication method that adds a digital signature to outgoing messages. Receiving servers verify the signature using a public key published in a [[dns|DNS]] record, confirming the email hasn't been altered in transit.
Example
When your email server sends a message, DKIM signs the headers and body. The recipient's server checks the signature against your DKIM DNS record.
Referenced in Guides
DNS Configuration