SPF, DKIM, and DMARC are three email authentication technologies that help to protect against email spoofing and phishing attacks.
- SPF (Sender Policy Framework) allows email senders to specify which servers are authorized to send email on behalf of their domain. When a mail server receives an email, it can check the SPF record for the sender’s domain to verify that the email is coming from a legitimate source.
- DKIM (DomainKeys Identified Mail) adds a digital signature to email messages, which can be verified by the recipient’s mail server. This helps to ensure that the email has not been tampered with since it was sent.
- DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on SPF and DKIM by allowing domain owners to specify how they want email that fails SPF or DKIM authentication to be handled. For example, a domain owner could choose to have all emails that fail SPF or DKIM authentication be rejected, or they could choose to quarantine them.
SPF records are stored in the Domain Name System (DNS) and contain a list of IP addresses that are authorized to send email on behalf of a domain. When a mail server receives an email message, it can check the SPF record for the sender’s domain to see if the IP address of the mail server that sent the message is listed in the record. If the IP address is not listed, the mail server may reject the message or quarantine it.
DKIM records are also stored in the DNS and contain the public key used to sign email messages. When a mail server receives an email message that is signed with DKIM, it can use the public key to verify the signature and confirm that the message was sent from the claimed sender.
DMARC records are also stored in the DNS and contain information about how the domain owner wants email that fails SPF or DKIM authentication to be handled. For example, a domain owner could choose to have all emails that fail SPF or DKIM authentication be rejected, or they could choose to quarantine them.
By using SPF, DKIM, and DMARC together, domain owners can significantly reduce the risk of email spoofing and phishing attacks.
Here are some of the benefits of using SPF, DKIM, and DMARC:
- Reduced risk of email spoofing and phishing attacks: SPF, DKIM, and DMARC can help to prevent email spoofing and phishing attacks by making it more difficult for attackers to send emails that appear to be from a legitimate sender.
- Improved email security: SPF, DKIM, and DMARC can help to improve email security by making it more difficult for attackers to tamper with email messages.
- Increased email deliverability: SPF, DKIM, and DMARC can help to increase email deliverability by making it more likely that email messages will be accepted by mail servers.
If you are a domain owner, I encourage you to implement SPF, DKIM, and DMARC to help protect your organization from email spoofing and phishing attacks.