Upgrading the firewall configuration from Plesk Onyx to Plesk Obsidian involves a few steps to ensure a smooth transition. Here's a guide to help you through the process:

1. Backup Your Data: Before making any major changes, it's crucial to create a backup of your server and firewall configurations. This provides a safety net in case anything goes wrong during the upgrade.

2. Check Compatibility: Verify that your current firewall configuration in Plesk Onyx is compatible with Plesk Obsidian. Consult the Plesk documentation or support resources for any specific requirements or recommendations.

3. Update Plesk Onyx: Ensure that you are running the latest version of Plesk Onyx before proceeding with the upgrade to Obsidian. This will help prevent any compatibility issues.

4. Upgrade to Plesk Obsidian: Follow the steps for upgrading Plesk Onyx to Plesk Obsidian. This may involve using the Plesk Installer, which will guide you through the upgrade process.

5. Verify Firewall Extensions: After upgrading to Plesk Obsidian, check if the firewall extensions and tools you were using in Onyx are compatible with Obsidian. Some extensions may need to be updated or replaced.

6. Review Firewall Settings: Access the firewall settings in Plesk Obsidian and review the configurations. Depending on your specific firewall solution (e.g., FirewallD, tables, etc.), you may need to reconfigure some rules or settings.

7. Migrate Rules (if necessary): If you were using a custom firewall configuration in Plesk Onyx, you may need to migrate these rules to the new firewall system in Plesk Obsidian. Consult the documentation for your specific firewall solution for guidance on migrating rules.

8. Test Firewall Rules: After making any necessary adjustments, thoroughly test your firewall rules to ensure they are functioning as expected. This can help identify and resolve any issues before they affect production environments.

9. Monitor and Fine-Tune: Keep an eye on your server's performance and security after the upgrade. Adjust firewall rules and configurations as needed to optimize performance and maintain security.

10. Regularly Update and Maintain: Stay proactive in keeping your firewall rules up-to-date with the latest security best practices and patches. Regularly review and adjust your configurations as necessary.

Remember, if you're unsure about any specific steps or configurations, it's always a good idea to consult with a system administrator or your hosting provider for guidance tailored to your specific setup.