.htaccess login twice answer

A client had an problem with their security login via an .htaccess file in a subdirectory of root called "catalog". "There are no other .htaccess files in any directories but for some reason I get asked to login twice when i access this page. It is successful after the second login. I can access a page on the root of my public-html dir without authentication and even another subdir of public-html without." The problem was the internal linking used both www.w3it.com and the w3it.com. To repair the problem: All hyperlinks to the same resource should be the same. Example: All these links point to the same place logically: /protected_dir/file.html http://w3it.com/protected_dir/file.html http://www.w3it.com/protected_dir/file.html However, Apache treats them as separate URL's, and will issue an extra login challenge for each. To fix the fault for the client we used this example for hyperlink structures throughout the protected area: http://www.w3it.com/catalog/ NOTE: If you do not link to a file, make sure you use the trailing /