For a network including multiple host machines that together implement at least one logical network including a firewall, some embodiments provide a method for collecting traffic flow data that includes identifiers for firewall rules applied to the traffic flow and a logical entity identifier. In some embodiments, the host machines receive traffic monitoring configuration data for a logical network. The traffic monitoring configuration data in some embodiments indicates a set of logical entities of the logical network for which to collect traffic flow data and a set of traffic flow data collectors associated with the set of logical entities. The indicated logical entities may be logical forwarding elements (logical switches, routers, etc.) or logical ports of logical forwarding elements.