US Patent 10949248 Load balancing and destination network address translation middleboxes

A controller of a network control system for configuring several middlebox instances is described. The middlebox instances implement a middlebox in a distributed manner in several hosts. The controller configures a first middlebox instance to obtain status of a set of servers and disseminate the obtained status to a second middlebox instance. The controller configures the second middlebox instance to use the status to select a server from the set of servers.