Drupal: Issue: Redirect page in Drupal

In my case I need to redirect from default main page to cas authentication page outsite server.

1. Go to Home> Administer> User Management> Cas Setting
   
   
2. Go to Redirection Setting
   
   
3. Edit at
   
   
   Require CAS login for:

   specific pages

   all pages except specific pages
   
   
   Specific pages:

   <front>

   Enter one page per line as Drupal paths. The '*' character is a wildcard. Example paths are 'blog' for the blog page and 'blog/*' for every personal blog. '' is the front page.
   
   

   Successful login message:

   The message displayed to a user when he successfully logs in via CAS. You may specify '%cas_username', the username of the user.

   Redirect user on logout
   
   

   Activate this option if you want a user to be directed to the following page after logging out of CAS. The logout destination must be specified below.

   Logout destination:

   URL. An example URL is 'http://www.example.com'.

   
   
4. ** In the website, remain link to the default portal url .
   
   
5. Refresh and test the changes. The link to the portal will redirect to cas login page.
   
   
6. Done.