Data filtering enables the firewall to detect sensitive information—such as credit card or social security numbers or internal corporate documents—and prevent this data from leaving a secure network. Before you enable data filtering, select Objects > Custom Objects > Data Patterns to define the type of data you want to filter (such as social security numbers or document titles that contain the word “confidential”). You can add several data pattern objects to a single Data Filtering profile and, when attached to a Security policy rule, the firewall scans allowed traffic for each data pattern and blocks matching traffic based on the data filtering profile settings.