Defining Rules for an Exempt Rulebase

The exempt rulebase works in conjunction with the IPS rulebase. Before you can create exempt rules, you must first create rules in the IPS rulebase. If traffic matches a rule in the IPS rulebase, IDP attempts to match the traffic against the exempt rulebase before performing the specified action or creating a log record for the event. If IDP detects traffic that matches the source/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 IDP 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 IDP rule. This prevents IDP from generating unnecessary alarms.

When you create an exempt rule, you must specify the following:

• Source and destination for traffic you want to exempt. You can set the source or destination to Any to exempt network traffic originating from any source or sent to any destination. You can also set source-except or destination-except to specify all the sources or destinations except the specified source or destination addresses.
• The attacks you want IDP to exempt for the specified source/destination addresses. You must include at least one attack object in an exempt rule.

  In this configuration example, you consistently find that your IDP policy generates false positives for the attack FTP:USER:ROOT on your internal network. You configure the rule to exempt attack detection for this attack when the source IP is from your internal network.

You can use either J-Web or the CLI configuration editor to configure an application set.

This topic contains:

• J-Web Configuration
• CLI Configuration
• Related Topics

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