DKIM (DomainKeys Identified Mail), DMARC (Domain-based Message Authentication, Reporting, and Conformance), and SPF (Sender Policy Framework) are email authentication protocols that work together to protect emails from spoofing, phishing, and other forms of email fraud. Here's how they work together:
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SPF (Sender Policy Framework):
SPF is an email authentication method that verifies the sender's IP address to ensure that it is authorized to send emails on behalf of a specific domain. The domain owner publishes SPF records in its DNS (Domain Name System) settings, specifying the IP addresses or hostnames of the servers authorized to send email for that domain. When an email is received, the recipient's mail server checks the SPF record of the sender's domain to verify if the IP address matches the authorized servers. If the SPF check fails, the email may be marked as suspicious or rejected. -
DKIM (DomainKeys Identified Mail):
DKIM is an email authentication method that provides a digital signature for each outgoing email. When an email is sent, the sender's mail server applies a private key to the email's header and body, generating a unique digital signature. The public key is published in the DNS records of the sender's domain. When the recipient's mail server receives the email, it retrieves the public key from the DNS and uses it to verify the authenticity and integrity of the email by decrypting the signature. If the verification fails or the DKIM signature is missing, the email may be treated as suspicious or unauthenticated. -
DMARC (Domain-based Message Authentication, Reporting, and Conformance):
DMARC is a policy framework that builds upon SPF and DKIM to provide enhanced email authentication and reporting capabilities. It allows domain owners to specify how receiving mail servers should handle emails that fail SPF or DKIM checks. With DMARC, the domain owner can set a policy that instructs the recipient's mail server to either reject, quarantine, or deliver the email normally when authentication fails. DMARC also enables the domain owner to receive reports from email receivers about the authentication results, providing insights into unauthorized use of their domain or email spoofing attempts.
When SPF, DKIM, and DMARC are used together, they provide a layered approach to email authentication and protection. SPF verifies the sending server's IP address, DKIM verifies the integrity and authenticity of the email's content, and DMARC sets policies for how to handle failed authentication. This combined approach helps prevent email spoofing, phishing attacks, and improves the overall security and trustworthiness of email communications.
