NearlyFreeSpeech.NET supports three types of canonical name settings:
off - This is the default type for new sites. The network attempts to avoid the use of a site's canonical name. Redirects issued by the network will use the hostname presented in the HTTP Host: header. From an application standpoint this means that the HTTP_HOST variable will be copied to the SERVER_NAME variable for each request. This setting is particularly suited to sites that vary their content based on which alias is used, such as Drupal or WordPress multi-site hosting.
soft - This type is no longer available; it is only applicable to sites already using it. The network will use the site's configured canonical name when needed, such as during redirects, but will accept requests for any other alias and deliver them if possible. The SERVER_NAME variable will contain the configured canonical name. The use of this setting is not recommended.
hard - The network will always use the site's configured canonical name. If a request arrives for a non-canonical name, the network will automatically, transparently issue a "301 Moved Permanently" redirect to the browser, causing it to switch to the correct name. This setting is particularly appropriate for sites with one correct name, but a number of other names that the site owner also wishes to accept.
The default canonical name of each site is its nfshost.com alias. If your site's shortname is example, then its default canonical name is example.nfshost.com. This is usually only relevant if your canonical type is not off.
Your site's canonical name and type settings are visible in the "Config Information" box on the Site Information page for that site. To make changes to your site's canonical name or type settings, use the "Set Canonical Name" action on the same page.
NOTE: Be sure you have already created the desired alias(es) and specify which alias is to be the canonical name, when requesting the "hard" type. See this FAQ entry for more information.