Authenticate (default):
The default Authenticate action WILL NOT authenticate the user if during policy evaluation the request also matches a deny rule. The purpose of using the Authenticate action is for efficiency. The logic is that since it has already been determined that the request will be denied, the ProxySG will not go through the additional steps to authenticate the user which saves time and resources on the ProxySG. Proxy administrators who DO NOT need to enforce an internet security policy that requires that they identify users attempting to access blocked sites will choose this option for performance purposes.
Force Authenticate:
The Force Authenticate action WILL authenticate the user even when the request also matches a deny rule. The purpose of using Force Authenticate is to ensure that usernames are logged even when the request will be denied. Proxy administrators who DO need to enforce an internet security policy that requires that they identify users attempting to access blocked sites will use this option for security purposes.
[Web Access Layer]
Rule #1: Source=Any, Destination=category=suspicious, Action=DENY
[Web Access Layer]
Rule #1: Source=User1, Destination=category=suspicious, Action=DENY
Rule #2: Source=Any, Destination=category=suspicious, Action=DENY
Result: A request for a suspicious site WILL BE authenticated to determine the username since Web Access Layer rule #1 has a user based condition.
Example #3:
[Web Authentication Layer]
Rule #1: Source=Any, Destination=Any, Action=Force Authenticate
[Web Access Layer]
Rule #1: Source=Any, Destination=category=suspicious, Action=DENY
Result: A request for a suspicious site WILL BE authenticated because a Force Authenticate action is matched even though there are no domain user/group based rules.