where yourdomain.com is your domain and authorizedlinksite.com is a site that can link to your restricted directory. There can be no, or multiple, such authorized link sites. Note that the trailing slashes (/) are important and must be included.
Now try to access the authorized directory from a link on your site, from a link on the authorized site(s), if any, and, if possible, from a link from an unauthorized site (to ensure that it is restricting access properly). The latter test can be conducted using a link from a sub-directory of your site (eg. http://www.yourdomain.com/somedirectory/) that is not listed as a valid referrer as well.
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