System 4.0.0.0 System.Enum To be added. The enumeration specifies when the should be enforced. Field 4.0.0.0 System.Security.Authentication.ExtendedProtection.PolicyEnforcement The is always enforced. Clients that don’t support extended protection will fail to authenticate. Field 4.0.0.0 System.Security.Authentication.ExtendedProtection.PolicyEnforcement The is never enforced and extended protection is disabled. Field 4.0.0.0 System.Security.Authentication.ExtendedProtection.PolicyEnforcement The is enforced only if the client and server supports extended protection.