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Resolve Email Delivery Issues with Cloudflare

When using Cloudflare’s nameservers, there can sometimes be issues with email delivery if the DNS records are not correctly configured. Here are steps to troubleshoot and resolve common issues:

Steps to Resolve Email Delivery Issues with Cloudflare

1. Verify DNS Records on Cloudflare

Log in to your Cloudflare account and navigate to the DNS settings for your domain. Ensure the following records are correctly set up:

  • MX Record: This should point to your mail server.
    • Name: @
    • Mail server: mail.yourdomain.com (or the appropriate mail server)
    • Priority: 10 (or appropriate priority)
  • A Record: This should point to your mail server’s IP address.
    • Name: mail
    • Content: Your mail server’s IP address
    • Proxy status: DNS only (not proxied, grey cloud)
  • SPF Record: This should include your mail server’s IP or domain.
    • Type: TXT
    • Name: @
    • Content: v=spf1 mx -all
  • DKIM Record: This should match the configuration on your mail server.
    • Type: TXT
    • Name: default._domainkey
    • Content: The DKIM key provided by your mail server
  • DMARC Record: This helps with email authentication.

2. Ensure Mail-Related Subdomains Are Not Proxied

In Cloudflare’s DNS settings, make sure that any subdomains related to mail (such as mail.yourdomain.com) are set to DNS only and not proxied (grey cloud). Cloudflare’s proxying can interfere with mail delivery.


3. Check Email Server Configuration

Make sure your email server is configured correctly to accept and send emails for your domain. Common issues include:

  • Firewall settings: Ensure ports 25 (SMTP), 465 (SMTPS), 587 (Submission), 993 (IMAPS), and 995 (POP3S) are open.
  • Postfix/Dovecot configuration: Ensure these services are correctly set up and running.

4. Test Email Delivery

You can test email delivery using command-line tools or email clients. For example, using telnet:

telnet mail.yourdomain.com 25

Or by sending a test email from an email client configured to use your mail server.

5. Review Mail Logs

Check the mail logs on your server for any errors or issues that might indicate why emails are not being received:

tail -f /var/log/mail.log

Look for any error messages or clues about what might be going wrong.

6. Review SPF, DKIM, and DMARC Configuration

Ensure that SPF, DKIM, and DMARC are correctly configured both in your DNS and on your mail server. Misconfigurations in these settings can lead to emails being rejected or marked as spam.

Example DNS Configuration

Here’s an example of how your DNS records might look in Cloudflare:

Conclusion

By ensuring that your DNS records are correctly configured in Cloudflare and verifying that your email server is set up properly, you should be able to resolve issues with email delivery. If problems persist, further detailed investigation into your mail server’s logs and configuration may be necessary.