Practical network support for IP traceback

This paper describes a technique for tracing anonymous packet flooding attacks in the Internet back towards their source. This work is motivated by the increased frequency and sophistication of denial-of-service attacks and by the difficulty in tracing packets with incorrect, or “spoofed”, source addresses. In this paper we describe a general purpose traceback mechanism based on prob-abilistic packet marking in the network. Our approach allows a victim to identify the network path(s) traversed by attack traffic without requiring interactive operational support from Internet Ser-vice Providers (ISPs). Moreover, this traceback can be performed “post-mortem ” – after an attack has completed. We present an im-plementation of this technology that is incrementally deployable, (mostly) backwards compatible and can be efficiently implemented using conventional technology. 1