In recent years, to efficiently defend network attack, traceback has been proposed to track dwon the source of attack. With the identifiability of traceback, security measure, such as isolation or others, can be carried out to do less harm in network. Because traceback mechanism is a critical part of the defense against network attack, its related technology and research has achieved more and more attention and development. This article describes the levels of traceback, focusing on analysis of issues of each traceback level and the corresponding technical, and tracking process conducted in-depth discussions on the track in order to give a comprehensive description of traceback and to improve the understanding of cyber attacks attribution.