Patent attributes
Some embodiments provide a method for a network controller that manages a plurality of managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical forwarding element. The method generates the packet according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method inserts the packet into a managed forwarding element associated with the particular source such that the managed forwarding element processes the packet as though the packet was received from the particular source. The method receives, from a set of managed forwarding elements, a set of messages regarding logical processing operations and physical forwarding operations that each managed forwarding element in the set of managed forwarding elements performs on the packet.