Understanding IPS Policies
An Intrusion prevention system (IPS) policy enables you to selectively enforce various attack detection and prevention techniques on network traffic passing through an IPS-enabled device. There are two types of policy options:
Group Policy—select this option, when you want to push a configuration to a group of devices. You can create rules for a group policy.
During a device assignment for a group policy, only devices from the current and child domains (with view parent enabled) are listed. Devices in the child domain with view parent disabled are not listed. Not all the group policies of the Global domain are visible in the child domain. Group policies of the Global domain (including All device policy) are not visible to the child domain, if the view parent of that child domain is disabled. Only the group policies of the Global domain, which has devices from the child domain assigned to it, are visible in the child domain. If there is a group policy in global domain with devices from both D1 and the Global domains assigned to it, only this group policy of the Global domain is visible in the D1 domain along with only the D1 domain devices. No other devices, that is the Device-Exception policy, of the Global domain is visible in the D1 domain.
You cannot edit a group policy of the Global domain from the child domain. This is true for All Devices policy as well. Modifying the policy, deletion of the policy, managing a snapshot, snapshot policy and acquiring the policy lock is also not allowed. Similarly, you cannot perform these actions on the Device-Exception policy of the D1 domain from the Global domain. You can prioritize group policies from the current domain. Group policies from the other domains are not listed.
Device Policy—Select this option, when you want to push a unique IPS policy configuration per device. You can create device rules for a device IPS policy.
Security Director views a logical system like it does any other security device, and it takes ownership of the security configuration of the logical system. In Security Director, each logical system is managed as a unique security device.
During a device assignment for a device policy, only devices from the current domain are listed.
If Security Director discovers the root logical system, the root lsys discovers all other user lsys inside the device.
An IPS policy consists of rulebases and each rulebase contains a set of rules. It allows you to define policy rules to match a section of traffic based on a zone, network, and application, and then take active or passive preventive actions on that traffic.
An IPS rulebase protects your network from attacks by using attack objects to detect known and unknown attacks. It detects attacks based on stateful signature and protocol anomalies.
An exempt rulebase works in conjunction with the IPS rulebase. You must have rules in the IPS rulebase before you can create exempt rules. If traffic matches a rule in the IPS rulebase, the IPS policy attempts to match the traffic against the exempt rulebase before performing the specified action or creating a log record for the event. If the IPS policy detects traffic that matches the source or destination pair and the attack objects specified in the exempt rulebase, it automatically exempts that traffic from attack detection.
Configure an exempt rulebase in the following conditions:
When an IPS rule uses an attack object group that contains one or more attack objects that produce false positives or irrelevant log records.
When you want to exclude a specific source, destination, or source-destination pair from matching an IPS rule. This prevents IPS from generating unnecessary alarms.
After you create an IPS policy by adding rules in one or more rulebases, you can publish or update the policy. You can also view a list of security devices with IPS policies assigned to them. This list assists you in viewing the details of all the IPS policies and rules assigned per device.