Firewall Builder consists of an object-oriented GUI and a set of policy compilers for various firewall platforms. In Firewall Builder, a firewall policy is a set of rules; each rule consists of abstract objects that represent real network objects and services (hosts, routers, firewalls, networks, protocols). Firewall Builder helps users maintain a database of objects and allows policy editing using simple drag-and-drop operations. Preferences and object databases are stored in XML format.