1. A machine-readable non-transitory storage medium having instructions therein, which when executed by a machine, cause the machine to perform a method, the method comprising: maintaining attributes for each of a set of network addresses assignable to a device capable of accessing a service via a domain name, wherein a set of servers with different server addresses are provided for the service of the domain name; determining a mapping relationship between the network addresses and a set of preferences among the servers based on the attributes, the mapping relationship specifying one or more of the preferences for each of the network addresses, wherein a plurality of the network addresses share a common one of the preferences in the mapping relationship; and generating an association data representing the mapping relationship, wherein the plurality of the network addresses are collectively represented in the association data to be associated with the common preference, the device, if assigned to one of the network addresses, to request the service via one of the servers according to a corresponding one preference, and wherein the request for the service from the device is directed to the one server according to the association data in real time asynchronous to the generation of the association data.