1. A method, comprising: populating cells in a relational database with network configuration data, each cell containing the network configuration data for one router in a communications network; receiving, at a configuration server, a configuration query specifying the one router in the communications network; querying the relational database for the one router specified in the database query; retrieving, from memory of the configuration server, a rule associated with the one router, the rule expressed as a list of enabled interfaces in the communications network and a router inventory of routers in the communications network; determining a prefix of an Internet Protocol address assigned to the one router exists in response to the one router being matched to both the list of enabled interfaces and to the router inventory of routers; deriving a view table by applying the rule; and sending the view table to the one router as a response to the configuration query.