To add an authentication server
See the Configuring Authentication Servers section to add the authentication servers.
Navigate to System Configuration >General Settings.
In the Administrators area, click Edit for the Administrator accounts.
Click the Authentication tab.
In the Authentication server drop-down menu, select the authentication server you added in Step 2.
Keep all other options as default.
Click Save.
Click Pending Changes in the upper-right of the page.
Click Apply Changes.