Provided is a network duplexing apparatus and method. The network duplexing apparatus includes a plurality of network interface units configured to store information of a flow flowing in the network interface units, provide the information of the flow to a master unit when the flow corresponds to an asymmetric flow, and request information of an opposite side flow of the flow from the master unit to receive the requested information, and the master unit configured to store the information of the flow provided from the network interface unit, determine whether the information of the opposite side flow of the flow is stored, and provide the information of the opposite side flow to the network interface unit when the information of the opposite side flow is stored.