1. A method of managing firewall rules, the method comprising: displaying a plurality of firewall rules enforced by a plurality of firewall devices in a datacenter, wherein the firewall devices comprise (i) firewall engines executing on host computing devices, (ii) network perimeter firewall devices, and (iii) firewall appliances; after receiving a set of filtering criteria, displaying a subset of the plurality of firewall rules that satisfy the set of filtering criteria; and after receiving a modification to a particular firewall rule in the displayed subset, modifying the particular firewall rule, wherein at least one firewall appliance is an application firewall gateway that performs deep packet inspection.