When sending outgoing mail from a Plesk server, it's important to follow best practices to ensure deliverability and maintain a good sender reputation. Here are some recommendations:

1. Use a Dedicated IP Address:

   • Assign a dedicated IP address for outgoing mail. This helps separate your email traffic from other services on the server and can prevent issues with blacklisting.

2. Configure Reverse DNS (rDNS):

   • Set up a valid reverse DNS record for your mail server's IP address. Many email providers use rDNS as a factor in their spam filtering algorithms.

3. Configure SPF and DKIM Records:

   • Implement Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) records for your domain. These authentication methods help verify that the email is sent from an authorized server.

4. Set up DMARC Policies:

   • Implement Domain-based Message Authentication, Reporting, and Conformance (DMARC) policies to provide further authentication and specify what action should be taken if SPF or DKIM checks fail.

5. Use a Valid "From" Address:

   • Ensure that the "From" address in your emails is valid and corresponds to a real domain associated with your server.

6. Avoid Sending Unsolicited Email (SPAM):

   • Only send emails to recipients who have opted in to receive them. Avoid purchasing or using email lists that haven't explicitly opted in.

7. Limit Sending Rate:

   • Configure your mail server to limit the number of outgoing emails per hour to prevent spamming and avoid being flagged by email providers.

8. Monitor for Abnormal Activity:

   • Set up monitoring and alerting systems to notify you of any unusual spikes in outgoing mail traffic, which could indicate a compromised account or spamming.

9. Implement Content Filters:

   • Use spam filters and content checks to identify and block or quarantine suspicious or malicious emails.

10. Regularly Update and Patch Software:

    • Keep your mail server software, including Plesk and mail services (e.g., Postfix), up to date to ensure you're protected against known vulnerabilities.

11. Monitor Blacklists:

    • Regularly check if your server's IP address or domain is blacklisted. There are online tools available for this purpose.

12. Maintain a Feedback Loop:

    • Set up a feedback loop with major email providers. This allows you to receive reports about emails that are marked as spam or have other delivery issues.

13. Provide Unsubscribe Options:

    • Include clear instructions on how recipients can opt out of receiving future emails from you.

14. Educate Users:

    • Educate users on your server about best practices for email, including avoiding suspicious attachments, not clicking on phishing links, and being cautious with email communications.

15. Use Encryption:

    • Implement TLS encryption for email communication to protect the content of emails in transit.

By following these best practices, you can help ensure that your outgoing emails are delivered reliably and that your server maintains a good sender reputation.