Before you can map the domain, you need to install the WordPress MU Domain Mapping plugin to help handle this in WordPress. The Domain Mapping plugin doesn't do any setup on the server side; it helps rename the site and takes care of any login issues.
Inside are two php files: domain-mapping.php and sunrise.php.
If you need a reminder on how to do this, see Chapter 1 of this minibook.
Figure 6-6 shows how these files look on the server. From here, you need to add a line to your wp-config.php file.
define( 'SUNRISE', 'on' );
The plugin is immediately available (and running) on your network. All you need to do is set up the options and map a domain to a site. Two new items are added to the Super Admin menu: Domain Mapping and Domains. On the user administrator side, a new Domain Mapping item appears on the Tools menu.
The network admin will need to activate domain mapping on the Domain Mapping page (Network AdminDomain Mapping) before a user can map a domain by enabling the Domain Mapping feature.
An IP address is a number assigned to every Web site and computer connected to the Internet. This number is used in domain mapping to help direct Internet traffic to the appropriate site in your network. You can find the IP address of your Web site three ways: Your Web host provider can tell you, the address may appear in some place within the Web host's control panel, and you can visit an IP lookup Web site. Such Web sites can tell you the IP of your Web site when you provide your domain name. To find your address with an IP lookup Web site, follow these steps:
Figure 6-7 displays the IP address of mommieblogs.com.
To map a domain to a site in your network, here's what you need to do:
The Domain Mapping page appears, as shown in Figure 6-8.
The check box indicates whether the domain is the primary domain for this site and is used only if you want to map multiple domains to the site. Only one domain can be the primary domain and used in the URL. Any other domains mapped to this site redirect to the primary domain.
The site now appears when you enter the mapped domain URL in your Web browser address bar.
This plugin also lets the network admin map a domain to a site without visiting the site's Dashboard. You can do this by choosing Network AdminDomains. (See Figure 6-9.) Note: You need to know the ID number of the site you want to map.