Onartline Multisite Domain Mapping

Installation

Important – Please Read Before Installing

This plugin is recommended for new WordPress Multisite network installations.

Installing Onartline Multisite Domain Mapping on an already existing, active Multisite network is not recommended and is done entirely at your own risk. It may interfere with existing domain configurations, redirects, or other plugins that handle similar functionality.

If you already run a Multisite network and want to use this plugin, it is strongly recommended to set up a fresh, new Multisite installation first, and then migrate or import your existing content and data into that new installation – rather than adding this plugin to your current, active network.

1. Upload the Plugin

Upload the onartline-multisite-domain-mapping folder to /wp-content/plugins/ or install it directly via the WordPress Network Admin under Plugins → Add New.

2. Activate the Plugin

Activate the plugin via Network Admin → Plugins → Network Activate.

3. Set Up sunrise.php

Onartline Multisite Domain Mapping requires sunrise.php to be loaded before WordPress initializes.

Automatic installation: If wp-content/ is writable, the plugin copies sunrise.php automatically on activation. You will see a success notice in the Network Admin.

Manual installation: If the automatic copy fails, copy sunrise.php manually:

1. Copy sunrise.php from the plugin folder to /wp-content/sunrise.php

2. Add the following line to your wp-config.php – directly before require_once ABSPATH . 'wp-settings.php';:

   define( ‘SUNRISE’, true );

4. Configure wp-config.php

Make sure the following line is present in your wp-config.php:

define( 'SUNRISE', true );

5. ⚠️ Plesk Users – Disable “Preferred Domain”

If your server runs Plesk, you must disable the “Preferred Domain” setting for each domain you want to map. Otherwise Plesk will intercept the redirect before WordPress can handle it, causing redirect loops or broken mappings.

1. Log in to Plesk
2. Go to Websites & Domains → your domain → Hosting Settings
3. Set Preferred Domain to None
4. Save the settings

6. Add Your First Domain Mapping

1. Go to Network Admin → Domain Mapping → Add Domain
2. Select the target site
3. Enter the domain (without http:// or https://)
4. Optionally set it as Primary Domain and enable HTTPS
5. Save

7. Configure DNS

Point your domain to your server by setting the following DNS records:

• A Record – Name: @ – Value: Your server IP address
• CNAME Record – Name: www – Value: Your primary domain or server CNAME

The required values are displayed in Network Admin → Domain Mapping → Settings.

8. Uninstallation

When you deactivate and delete Onartline Multisite Domain Mapping via Network Admin → Plugins, the plugin automatically removes:

• The plugin files
• The sunrise.php file from /wp-content/
• The database tables (only if “Delete data on uninstall” was enabled in the plugin settings)

Important – Manual step required

The plugin cannot automatically remove the following line from your wp-config.php:

define( 'SUNRISE', true );

This line was added manually during installation and must also be removed manually after uninstalling the plugin. If this line remains in wp-config.php after sunrise.php has been deleted, WordPress will try to load a file that no longer exists, resulting in warnings such as:

Warning: include_once(.../wp-content/sunrise.php): Failed to open stream: No such file or directory

and potentially headers already sent errors on the login page or elsewhere.

To fix this: Open your wp-config.php and remove (or comment out) the line define( 'SUNRISE', true );, then save the file.