Doing route selection based in part on source addresses is a form of policy routing, which has started to receive increased amounts of attention. In this paper, we extend our previous work on ROLF (ROuting as the Firewall Layer) to achieve source prefix filtering. This permits easy definition of "inside" and "outside", even in MANET environment where there is no topological boundary. We present algorithms for route propagation and packet forwarding using ROFL; we measure its performance in a

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... ulated environment with two different ad hoc routing protocols. Simulation results demonstrate that ROFL can significantly reduce unwanted packets without extra control traffic incurred, and thus improves overall system performance and preserves battery power of mobile nodes. ROFL is the first scheme to provide a concrete defense against some battery exhaustion attacks in MANETs. Moreover, it requires only minor changes to existing ad hoc network routing protocols, making it practical and feasible to be deployed in real world.