The Denial-of-Service (DoS) attack remains a challenging problem in the current Internet. In a DoS defense, mechanism, a honeypot acts as a decoy within a pool of servers, whereby any packet received by the honeypot is most likely an attack packet. We have previously proposed the roaming honeypots scheme to enhance this mechanism by camouflaging the honeypots within the server pool, thereby making their locations highly unpredictable. In roaming honeypots, each server acts as a honeypot for some periods of time, or honeypot epochs, the duration of which is determined by a pseudo-random schedule shared among servers and legitimate clients. In this paper, we propose a honeypot backpropagation scheme to trace back attack sources when attacks occur. Based on this scheme, the reception of a packet by a roaming honeypot triggers the activation of a DAG of honeypot sessions rooted at the honeypot under attack towards attack sources. The formation of this tree is achieved in a hierarchical fashion: first at the Autonomous system (AS) level and then at the router level within an AS if needed. The proposed scheme supports incremental deployment and provides deployment incentives for ISPs. Through ns-2 simulations, we show how the proposed scheme enhances the performance of a vanilla Pushback defense by obtaining accurate attack signatures and acting promptly once an attack is detected.