Setting up a WordPress multisite network allows you to manage multiple websites from a single WordPress installation, sharing core files, plugins, and themes while maintaining separate content and user roles. This is particularly useful for educational institutions, businesses with multiple divisions, or developers managing client sites. The process involves modifying core configuration files, choosing between subdomain or subdirectory structures, and configuring network settings through the WordPress dashboard.

Key findings from the search results:

• Core requirement: You must edit the wp-config.php file to enable multisite by adding define('WPALLOWMULTISITE', true); ^[1][2][8]
• Setup options: Choose between subdomains (e.g., site1.yourdomain.com) or subdirectories (e.g., yourdomain.com/site1) during network installation ^[2][4][9]
• Critical steps: After enabling multisite, you must update both wp-config.php and .htaccess (or nginx.conf for Nginx servers) with provided code snippets ^[2][8]
• Hosting considerations: Multisite works best on VPS or dedicated hosting; shared hosting may limit functionality or require wildcard subdomain support ^[3][6]

Step-by-Step WordPress Multisite Setup Process

Preparing Your WordPress Installation

Before enabling multisite, ensure your WordPress installation meets the technical requirements and is properly backed up. This step prevents data loss and compatibility issues during the transition.

The preparation phase includes deactivating plugins, verifying permalinks, and confirming server support for wildcard subdomains (if using subdomains). According to the WordPress Advanced Administration Handbook, you must:

• Backup your entire site, including the database and all files, as the multisite setup modifies core configurations ^[2][8]
• Enable Pretty Permalinks in Settings > Permalinks to ensure the network functions correctly. The default "Plain" permalink structure is incompatible with multisite ^[2][8]
• Deactivate all plugins to avoid conflicts during installation. Plugins can be reactivated after the network is fully configured ^[8]
• Verify server compatibility:
• Apache servers require .htaccess file modifications ^[2]
• Nginx servers need manual configuration in nginx.conf ^[1]
• Wildcard subdomains (e.g., *.yourdomain.com) must be supported if using subdomains ^[5][6]

Hosting providers like WP Engine and Cloudways note that multisite is often restricted to premium plans due to resource demands. Shared hosting may lack wildcard subdomain support or sufficient database capacity ^[7][9].

Enabling and Configuring the Multisite Network

Once prepared, the next step is to enable multisite by editing the wp-config.php file and completing the network setup via the WordPress dashboard. This process is irreversible, so careful execution is critical.

Step 1: Enable Multisite in wp-config.php

Add the following line above the / That's all, stop editing! / comment in your wp-config.php file:

define('WPALLOWMULTISITE', true);

This line signals WordPress to display the Network Setup menu under Tools in the dashboard ^[1][2][8].

Step 2: Run the Network Setup

After saving wp-config.php, refresh your WordPress dashboard and navigate to Tools > Network Setup. Here, you will:

• Choose your network structure:
• Subdomains (e.g., site1.yourdomain.com) – Requires wildcard DNS configuration ^[5][6]
• Subdirectories (e.g., yourdomain.com/site1) – Simpler but less scalable for large networks ^[4]
• Enter network details:
• Network Title: The name of your multisite network (e.g., "My Business Sites")
• Admin Email: The email for the Super Admin account (this user manages the entire network) ^[2][9]

WordPress will generate two code snippets after submission. Do not close this page until you’ve added both snippets to their respective files.

Step 3: Update Configuration Files

The generated snippets must be added to:

1. wp-config.php (above the / That's all, stop editing! / line):

define('MULTISITE', true);
define('SUBDOMAININSTALL', true); // Only if using subdomains define('DOMAINCURRENTSITE', 'yourdomain.com'); define('PATHCURRENTSITE', '/'); define('SITEIDCURRENTSITE', 1); define('BLOGIDCURRENT_SITE', 1);

1. .htaccess (for Apache) or nginx.conf (for Nginx):

RewriteEngine On
RewriteBase / RewriteRule ^index\.php$ - [L] add a trailing slash to /wp-admin RewriteRule ^wp-admin$ wp-admin/ [R=301,L] RewriteCond %{REQUESTFILENAME} -f [OR] RewriteCond %{REQUESTFILENAME} -d RewriteRule ^ - [L] RewriteRule ^(wp-(content|admin|includes).) $1 [L] RewriteRule ^(.\.php)$ $1 [L] RewriteRule . index.php [L]

Step 4: Log In and Configure the Network

After updating the files, log out and log back into WordPress. You will now see a Network Admin menu in the dashboard. Key post-setup tasks include:

• Adding new sites: Navigate to My Sites > Network Admin > Sites > Add New to create subsites ^[3][8]
• Managing themes/plugins: Only the Super Admin can install or delete themes/plugins; individual site admins can only activate/deactivate them ^[4][7]
• User roles: Assign roles such as Site Admin (manages a single site) or Super Admin (manages the entire network) ^[4]

Post-Setup Considerations and Troubleshooting

• Wildcard subdomains: If using subdomains, configure a wildcard DNS record (e.g., *.yourdomain.com) to point to your server’s IP ^[5][6].
• Plugin compatibility: Some plugins (e.g., caching or security plugins) may not support multisite. Test plugins in a staging environment first ^[3][10].
• Performance impact: Shared resources mean one site’s traffic spike can affect others. Consider dedicated hosting for high-traffic networks ^[3][6].
• Domain mapping: Use plugins like WordPress MU Domain Mapping to assign custom domains to subsites ^[4][7].