In this paper authors present a new method to organize hardware search in the tables of rules in the software defined network (SDN) switch. This paper describes the design features of modern SDNs based on open standard OpenFlow, main problems of modern OpenFlow switches, and proposes a new approach for building hardware search based on field-programmable gate arrays (FPGAs). The proposed method allows searching by mask in all bits of the header of incoming packages and therefore to expand usability of the SDNs.