Static assignment of IP addresses or identifiers can be exploited by an adversary to attack a network.However,existing dynamic IP address assignment approaches suffer from two limitations,namely: participation of ter-minals in the assignment and inadequate net-work server management.Thus,in this paper,we propose an Overall-transparent Dynamic Identifier-mapping Mechanism(ODIM)to manage the identifier of network nodes to de-fend against scanning and worm propagation in the Smart Identifier NETwork(SINET).We establish the selection and allocation con-straints,and present selection and allocation algorithms to determine the constraints.The non-repetition probability and cover cycle allow us to evaluate the defense efficiency against scanning.We propose the probability for routing identifiers and derive the defense efficiency of ODIM against worm propaga-tion.Simulation results and theoretical analy-sis show that the proposed method effectively reduces the detection probability of Routing IDentifiers(RIDs)and thus improves defense capabilities against worm propagation.