How to Set Up SPF, DKIM, and DMARC for Your Mail Server

How to Set Up SPF, DKIM, and DMARC for Your Mail Server

Setting up SPF, DKIM, and DMARC records is essential for improving email deliverability and protecting your domain from spoofing and phishing. This guide will walk QuickServers.net customers through the process of configuring these email authentication methods on your dedicated server.

Step 1: Understand SPF, DKIM, and DMARC

• SPF (Sender Policy Framework): Defines which mail servers are authorized to send emails on behalf of your domain.
• DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails to verify their authenticity.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): Specifies how to handle emails that fail SPF or DKIM checks and provides reports on email activity.

Step 2: Configure SPF Records

• Access your domain's DNS management tool.
• Add a TXT record for your domain with the following format:

  Name: @  
  Type: TXT  
  Value: v=spf1 ip4:<Your Server IP> include:<Mail Provider> -all  
  

  • Replace <Your Server IP> with your dedicated server’s IP address.
  • Replace <Mail Provider> with any additional mail services you use (e.g., Gmail or Office365).
  • The -all directive ensures that only the specified IPs are authorized to send emails.

Step 3: Generate and Configure DKIM Keys

• Use your mail server software to generate DKIM keys. For example:
  • Postfix: Use tools like opendkim-genkey.
  • Exim: Enable DKIM signing in the configuration file.
• The generated public key will need to be added to your DNS as a TXT record. Example:

  Name: default._domainkey  
  Type: TXT  
  Value: v=DKIM1; k=rsa; p=<Your Public Key>  
  

  • Replace <Your Public Key> with the generated key.
  • Keep the private key securely on your server.

Step 4: Set Up DMARC Records

• Add a TXT record for your domain with the following format:

  Name: _dmarc  
  Type: TXT  
  Value: v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@yourdomain.com;  
  

  • Replace dmarc-reports@yourdomain.com with your email address to receive reports.
  • Adjust the p= policy to none, quarantine, or reject based on your preferences.

Step 5: Verify DNS Propagation

• Use tools like dig, nslookup, or online DNS record checkers to confirm that your SPF, DKIM, and DMARC records are correctly configured.
• Look for errors or warnings that might indicate incorrect entries.

Step 6: Test Your Configuration

• Send test emails to services like Mail Tester or Gmail to confirm that your emails pass SPF, DKIM, and DMARC checks.
• Check email headers to verify authentication results.

Step 7: Monitor Reports and Adjust Settings

• Review DMARC reports to identify unauthorized email activity.
• Fine-tune your SPF, DKIM, and DMARC policies if needed to improve email security.

Conclusion
By properly setting up SPF, DKIM, and DMARC records, you can secure your mail server and ensure reliable email delivery. Regularly monitor your email activity to maintain optimal security and performance.