WordPress.org

1. Copy sunrise.php into wp-content/. If there is a sunrise.php there already, you'll just have to merge them as best you can.
2. Copy domain_mapping.php into wp-content/mu-plugins/.
3. Edit wp-config.php and uncomment the SUNRISE definition line: define( 'SUNRISE', 'on' );
4. As a "site admin", visit Site Admin->Domain Mapping to create the domain mapping database table and set the server IP address or a domain to point CNAME records at.
5. Make sure the default Apache virtual host points at your WordPress MU site so it will handle unknown domains correctly. (Need info on cpanel, etc. How do you get them to respond to any domain?)
6. Do not define COOKIE_DOMAIN in your wp-config.php as it conflicts with logins on your mapped domains.

For Cpanel users

If your domain uses the nameservers on your hosting account you should follow these instructions. If the nameservers are elsewhere change the A record or CNAME as documented above. Add a wildcard subdomain/virtual host record to your site's DNS record in Web Host Manager (WHM). If you do not have access to WHM, you must email your web host and ask them to make this one change for you. Should be no problem:

• Go to "Edit DNS Zone" and select the domain of your WPMU installation and click "Edit".
• Below "Add New Entries Below This Line", enter in the first box (Domain) an asterisk: "*".
• The second box, TTL, should be "14400".
• The third box should be "IN".
• Select A Record Type from the drop down "A".
• And in the last box, paste in the IP address of your website.

From Cpanel, click on the "Parked Domains" under the "Domains" section:

• Under "Create a New Parked Domain" enter the domain name you want to add to your site.
• Click the "Add Domain" button.
• It should add the domain to the list of parked domains and under "Redirect to" it will say "not redirected". That is OKAY.

Now you're ready to do your domain mapping.