The dynamic average consensus problem in multi-agent networks is considered. Each agent residing on the network establishes a dynamic average consensus estimator whose output tracks the average of time-varying inputs to all the agents in the network. The authors propose a systematic methodology to construct any dynamic linear protocol for the dynamic average consensus having desired stability and performance properties. Our aim is to reduce the design problem of the dynamic average consensus protocols to the design problem of a simple system constructed of a simple integrator with a disturbance rejection controller as a feedback control. The authors rigorously analyse the input-to-state stability and some important performance properties of the dynamic linear protocol. The important case of switching topology is precisely analysed and therefore sufficient conditions for the uniform-input-to-state stability of the switched dynamic average consensus estimators are identified. Also the cases of initialisation errors and uniform time delays are well addressed. The case of addition/deletion of the agents is also pointed out. A design example of the dynamic linear protocol and its simulation results is presented demonstrating the efficiency of the proposed method.