How to Configure DKIM in Your FortiGate Firewall

The purpose of this article is to explain how to configure DKIM in your FortiGate firewall. Configuring DKIM (DomainKeys Identified Mail) for a FortiGate firewall involves a few steps to generate keys, set up DNS records, and enable DKIM signing for outgoing emails. Here’s a high-level guide on how to configure DKIM for a FortiGate firewall:

Step 1: Generate DKIM Keys

1. Access the FortiGate Web Interface:
   • Log in to the FortiGate web interface using your administrator credentials.
2. Navigate to Email Security Settings:
   • Locate and navigate to the email security settings in the FortiGate web interface. This may vary depending on the FortiGate model and firmware version.
3. Generate DKIM Keys:
   • Look for the option to generate DKIM keys. FortiGate typically provides a feature to generate the necessary cryptographic keys for DKIM.

Step 2: Add DKIM DNS Records

1. Retrieve DKIM Public Key:
   • After generating DKIM keys, retrieve the public key from the FortiGate interface. This key is essential for configuring DNS records.
2. Access DNS Management Console:
   • Log in to your domain’s DNS management console. This could be provided by your domain registrar or hosting provider.
3. Add DKIM TXT Records:
   • Add a TXT record in the DNS settings with the DKIM public key obtained from the FortiGate. The record should be in the format specified by DKIM standards.

Name: default._domainkey.yourdomain.com
Type: TXT
Value: DKIM_public_key

1. Replace “yourdomain.com” with your actual domain and “DKIM_public_key” with the public key provided by FortiGate.

Step 3: Enable DKIM Signing

1. Return to FortiGate Web Interface:
   • Go back to the FortiGate web interface.
2. Configure Email Security Settings:
   • Navigate to the email security settings, specifically the section related to DKIM.
3. Enable DKIM Signing:
   • Look for an option to enable DKIM signing for outgoing emails. This setting is usually found within the email security configuration.

DKIM Signing: Enable

Step 4: Test DKIM Configuration

1. Send a Test Email:
   • Send a test email from your domain to an external email address.
2. Check DKIM Signature:
   • Ask the recipient to check the email headers for the DKIM signature. They can use email client tools or online DKIM verification services to confirm that the DKIM signature is present and valid.

Additional Considerations:

• Key Rotation: Consider implementing a key rotation policy to regularly update DKIM keys for enhanced security.
• Logging and Monitoring: Enable logging and monitoring features in FortiGate to keep track of DKIM-related events and potential issues.

It’s important to note that the exact steps and menu options may vary depending on the FortiGate firmware version and model. Always refer to the FortiGate documentation specific to your environment for the most accurate and up-to-date instructions.