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> Chapter 25 - Security Profiles > Intrusion protection > Enable IPS packet logging

Enable IPS packet logging

Packet logging saves the network packets containing the traffic matching an IPS signature to the attack log. The FortiGate unit will save the logged packets to wherever the logs are configured to be stored, whether memory, internal hard drive, a FortiAnalyzer unit, or the FortiGuard Analysis and Management Service.

You can enable packet logging in the filters. Use caution in enabling packet logging in a filter. Filters configured with few restrictions can contain thousands of signatures, potentially resulting in a flood of saved packets. This would take up a great deal of space, require time to sort through, and consume considerable system resources to process. Packet logging is designed as a focused diagnostic tool and is best used with a narrow scope.

note icon Although logging to multiple FortiAnalyzer units is supported, packet logs are not sent to the secondary and tertiary FortiAnalyzer units. Only the primary unit receives packet logs.
To enable packet logging for a filter
  1. Create a filter in an IPS sensor.
  2. After creating the filter, right-click the filter, and select Enable under Packet Logging.
  3. Select the IPS sensor in the security policy that allows the network traffic the FortiGate unit will examine for the signature.

When you enable packet

IPS logging changes

IPS operations severely affected by disk logging are moved out of the quick scanning path, including logging, SNMP trap generation, quarantine, etc.

Scanning processes are dedicated to nothing but scanning, which results in more evenly distributed CPU usage. Slow (IPS) operations are taken care of in a dedicated process, which usually stays idle.

note icon Setting packet‑log-history to a value larger than 1 can affect the performance of the FortiGate unit because network traffic must be buffered. The performance penalty depends on the model, the setting, and the traffic load.