For any business, ensuring the email authenticity and integrity, especially to customers, is crucial. One powerful tool designed to enhance email security is DKIM, or “DomainKeys Identified Mail”. DKIM helps to protect your email domain from being misused for malicious purposes and ensures that your emails reach their intended recipients without being modified. In this post, we’ll look at what DKIM is, how it works, and why it’s important for email security.

So What is DKIM?

DomainKeys Identified Mail (DKIM) is an email authentication method that uses cryptographic signatures to verify that an email was sent by an authorized mail server and that its content has not been altered during transit. None technical version is the sending server signs each email as it goes out and the receiving server verifies the signature. If a server that isn’t authorized to send emails for your domain sends an email it will not be verified by the receiving server and will be discarded or put into Spam.

How Does DKIM Work?

  1. First Step is to Sign the Email:
    • When an email is sent from a domain that uses DKIM, the email server generates a unique signature based on the email’s content and a private key. This signature is added to the email header as a DKIM-Signature field.
  2. Publishing DKIM Records:
    • The domain owner publishes a DKIM public key in DNS (Domain Name System) as a TXT record. This public key is used by recipient’s mail servers to verify the DKIM signature created in the first step.
  3. Verification Process:
    • When the recipient’s mail server receives the email, it retrieves the public key from DNS and uses it to verify the DKIM signature. If the signature is valid the email passes the DKIM check, if it is not valid the email should be rejected to sent to SPAM.

Why is DKIM Important?

  1. DKIM helps ensure that the content of your email hasn’t been altered during transit. If someone changes the email, the DKIM signature will no longer match, alerting the recipient to potential tampering.
  2. Emails authenticated with DKIM are less likely to be flagged as spam or phishing attempts. This improves deliverability and builds trust with your customers.
  3. By verifying that an email was sent from an authorized server, DKIM helps prevent email spoofing, where malicious actors attempt to impersonate your domain.

How to Implement DKIM

  1. First create a DKIM key pair (public and private keys). Most email service providers offer tools or instructions for generating these keys. Services like MonitorDMARC offer this as part of their Free plan.
  2. Publish the DKIM public key in your domain’s DNS settings as a TXT record. This allows recipient mail servers to access the key for verification.
  3. Configure your email server to sign all outgoing emails with the DKIM private key. This ensures that every email sent from your domain includes a valid DKIM signature.
  4. Use DKIM validation tools like MonitorDMARC to test your setup and monitor your email traffic to ensure that DKIM is functioning correctly.

Conclusion

DKIM is an important part of email security that helps to protect your domain from misuse and ensures the integrity of your emails. By implementing DKIM, you can prevent email tampering, build trust with your customers, and enhance your email deliverability. For a more comprehensive email security strategy, consider using DKIM in conjunction with other authentication protocols such as SPF (Sender Policy Framework) and DMARC (Domain-based Message Authentication, Reporting, and Conformance). Consider using a third party solution like MonitorDMARC to help you configure and monitor your email domains.