Probabilistic packet marking (PPM) has been studied as a promising approach to realize IP traceback. In this paper, we propose a new PPM approach that improves the current state of the art in two practical directions: (1) it improves the efficiency and accuracy of IP traceback and (2) it provides incentives for ISPs to deploy IP traceback in their networks. Our PPM approach employs a new IP header encoding scheme to store the whole identification informationof a router into a single packet. This eliminates the computation overhead and false positives due to router identification fragmentation. Our approach does not disclose the IP addresses of the routers having marked packets, thereby alleviating the ISP’s security concern of disclosing network topology. Our approach is able to control the distribution of marking information. So it is suitable to be implemented as a value-added service which may create revenue for ISPs. Therefore our PPM approach improves the performance and pra...