By default, authentication polices are validated first against policies that you bind to the virtual server and then against policies bound globally. If you bind an authentication policy globally and want the global policy to take precedence over a policy that you bind to a virtual server, you can change the priority number of the policy. Priority numbers start at zero. A lower priority number gives the authentication policy higher precedence.
For example, if the global policy has a priority number of one and the virtual server has a priority of two, the global authentication policy is applied first.
You can also modify an authentication policy that is bound to a virtual server.