An IDP policy defines how your device handles the network traffic. It allows you to enforce various attack detection and prevention techniques on traffic traversing your network.
A policy is made up of rulebases and each rulebase contains a set of rules. You define rule parameters, such as traffic match conditions, action, and logging requirements, then add the rules to rule bases. After you create an IDP Policy by adding rules in one or more rulebases, you can select that policy to be the active policy on your device.
JUNOS software with enhanced services allows you to configure multiple IDP policies, but a device can have only one active IDP policy at a time. You can install the same IDP policy on multiple devices, or you can install a unique IDP policy on each device in your network. A single policy can contain only one instance of any type of rulebase.