IP Traceback - Out-of-band Approaches

Out-of-band Approaches

The ICMP traceback scheme Steven M. Bellovin proposes probabilistically sending an ICMP traceback packet forward to the destination host of an IP packet with some low probability. Thus, the need to maintain state in either the packet or the router is obviated. Furthermore, the low probability keeps the processing overhead as well as the bandwidth requirement low. Bellovin suggests that the selection also be based on pseudo-random numbers to help block attempts to time attack bursts. The problem with this approach is that routers commonly block ICMP messages because of security issues associated with them.